<PAGE>

                                                                   EXHIBIT 10.18

TRIO-TECH

25 November 1999

Marketing & Sales Department                 [STAMP]      BY HAND
                                                          -------
Jurong Town Corporation
Jurong Town Hall
301 Town Hall Road
Singapore 609431


Dear Ms Lai Get Luan

ACCEPTANCE OF OFFER OF TENANCY FOR THE PREMISES AT BLK 1008 TOA PAYOH NORTH #03-
09 TO #03-18 TOA PAYOH INDUSTRIAL ESTATE SINGAPORE 318996


1.   We refer to your letter of dated 13 October 1999 and a letter of amendment
     dated 19 November 1999 for the Tenancy and hereby confirm our acceptance of
     all the covenants, terms and conditions stipulated therein.

2.   We enclose herewith a cheque for the amount of $13,403.90 and the Banker's
     guarantee as security deposit as confirmation of our acceptance.

3.   In addition, we also enclose herewith a duly completed GIRO authorization
     form as requested by you for your information and record.


                                 By: /s/ Yong Siew Wai
--------------------------------------------------------------------------------
Name of authorized signatory  :  Mr.Yong Siew Wai
Designation President         :  Chief Executive Officer
For and on behalf of

TRIO-TECH INTERNATIONAL PTE LTD

In the presence of:


                                 By: /s/ Betty Ang
--------------------------------------------------------------------------------
Name of witness               :  Ms. Betty Ang
NRIC No.                      :  S6945849A
<PAGE>

JTC(L)3601/2506/LGL/SN

                                                      DID: 5688574
                                                      FAX: 5688593
                                                      Email: getluan@jtc.gov.sgw
19 November, 1999

                                                      J T C
Trio-Tech International Pte Ltd
5 Kian Teck Rd
Singapore 628765

                                                   BY FAX @ 264 2235 & BY LUM
                                                   --------------------------
(Attn: Mrs Lee Siew Kuan/Ms Betty Ang)

Dear Sirs

AMENDMENT TO LETTER OF OFFER OF TENANCY IN RESPECT OF THE PREMISES AT BLK 1008
TOA PAYOH NORTH #03-09 TO #03-18 TOA PAYOH INDUSTRIAL ESTATE

1    We refer to your letter dated 15 November 1999 and our letter of offer
     dated 13 October 1999.

2    We are agreeable to your request to defer the commencement date of the said
     tenancy from 01 January 1999 to 16 January 2000. Hence, our letter of offer
     dated 13 October 1999 shall be amended as follows:-

     Sub-Paragraph 1.02:
     -------------------
     Term of Tenancy:
     ----------------

     3 years ("the Term") with effect from 16 January 2000 ("the Commencement
     Date").

     Sub-Paragraph 1.05:
     -------------------
     Rent and Service Charge:
     ------------------------
     Standard Rent:
     --------------

     (a)  Discounted rate of $12.03 per square metres for so long as the Tenant
          shall occupy by way of tenancy an aggregate floor area of not less
          than 1,000 square metres in the Building or in the various flatted
          factories belonging to the Landlord, and
<PAGE>

                                                                   2

                                                         Jurong Town Corporation

     (b)  Normal rate of $12.40 per square metres with effect from the date the
          said aggregate floor area occupied is reduced to below 1,000 square
          metres (i.e. when the discount shall be totally withdrawn),

          ("Rent") to be paid without demand and in advance without deduction on
          the 1st day of each month of the year (i.e. 1st of January, February,
          March, etc.). The next payment shall be made on 01 February 2000.

          Service charge:

          $2.10 per square metre per month, ("Service Charge") as charges for
          services rendered by us, payable without demand on the same date and
          in the same manner as the Rent, subject to our revision from time to
          time.

     Sub-Paragraph 1.06:
     -------------------
     Security Deposit/Banker's Guarantee:
     ------------------------------------

     You will at the time of acceptance of the Offer be required to place with
     us a deposit of $37,667.75 equivalent to 3 months' Rent (at the discounted
     rate) and Service Charge ("Security Deposit") as security against any
     breach of the covenants, terms and conditions in the Tenancy.

     The Security Deposit may be in the form of cash and/or acceptable Banker's
     Guarantee in the form attached (effective from 16 November 1999 to 15 July
     2003) and/or such other form of security as we may in our absolute
     discretion permit or accept.

     The Security Deposit must be maintained at the same sum throughout the Term
     and shall be repayable to you without interest or returned to you for
     cancellation, after the termination of the Term (by expiry or otherwise) or
     expiry of the Banker's Guarantee, as the case may be, subject to
     appropriate deductions or payment to us for damages or other sums due under
     the Tenancy.

     If the Rent at the discounted rate is increased to the normal rate or
     Service Charge is increased or any deductions are made from the Security
     Deposit, you are to immediately pay the amount of such increase or make
     good the deductions so that the Security Deposit shall at all times be
     equal to 3 months' Rent and Service Charge.

     Paragraph 2:
     ------------
     Mode of Acceptance
     ------------------

     The Offer shall lapse if we do not receive the following by 22 November
     1999:-

     .    Duly signed letter of acceptance (in duplicate) of all the covenants,
          terms and conditions in the Tenancy in the form enclosed at the
          Appendix.
          (Please date as required in the Appendix)
     .    Payment of the sum set out in clause 4.
     .    Duly completed GIRO authorization form.
<PAGE>

                                                                   3

                                                         Jurong Town Corporation

3    The Statement of Account in paragraph 4 of our offer is adjusted
     accordingly as follows:-

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------------------------
                                                     AMOUNT                              +3% GST
--------------------------------------------------------------------------------------------------
<S>                                                  <C>               <C>               <C>
Rent:
-----
Rent at $12.03 psm per month on 888.60
sqm for period 16 January 2000 to
15 February 2000                                     $10,689.86

Less:
6.6% Property tax rebate on rental value
(01/07/1998 to 30/06/2000)                           $   705.53
                                                     ----------
                                                     $ 9,984.33
--------------------------------------------------------------------------------------------------
Service Charge:
---------------
Service Charge at $2.10 psm per month
on 888.60 sqm for period
16 January 2000 to I5 February 2000                  $ 1,866.06        $11,850.39          $355.51
                                                     ----------
--------------------------------------------------------------------------------------------------
Deposit equivalent to three months' rent
and service charge (or Banker's Guarantee
provided in accordance with sub-paragraph
1.06 above)                                                            $37,667.75
--------------------------------------------------------------------------------------------------
Stamp fee payable on Letter of Acceptant
which will be stamped by JTC on your
behalf                                                                 $ 1,198.00
--------------------------------------------------------------------------------------------------
Sub-Total Payable                                                      $50,716.14          $355.51
--------------------------------------------------------------------------------------------------
Add: 3 % GST                                                           $   355.51
                                                                       ----------
--------------------------------------------------------------------------------------------------
Total Amount Payable                                                   $51,071.65
                                                                       ----------
--------------------------------------------------------------------------------------------------
</TABLE>
<PAGE>

                                                                   4

                                                         Jurong Town Corporation

4    All other terms and conditions stipulated in our letter of offer dated 13
     October 1999 remain unchanged.

5    Please let us have your letter of acceptance of the terms and conditions
     stipulated in our letter of offer dated 13 October 1999 and the above
     amendments together with your remittance amounting to $51,071.65.
     (Alternatively, you may wish to produce a cheque of $13,403.90 together
     with a Banker's Guarantee in lieu of the cash deposit of $37,667.75) by 22
     November 1999.

6    We enclose herewith a draft of the letter of acceptance and the Banker's
     Guarantee format for your use/reference.



Yours faithfully



By: /s/ Lai Get Luan

LAI GET LUAN (Ms)
MARKETING & SALES DEPARTMENT
INDUSTRIAL PARKS DEVELOPMENT GROUP
JURONG TOWN CORPORATION

Attd: Draft of letter of acceptance
      Banker's Guarantee format
<PAGE>

JTC(L)3601/2506/LGL1SN                                 DID: 5688574
                                                       FAX: 5688593
                                                       Email: getluan@jtc.gov.sg

13 October 1999

Trio-Tech International Pte Ltd
5 Kian Teck Rd                                         BY FAX @ 264 2235
                                                       -----------------
Singapore 628765                                       & BY LUM
                                                       --------

(Attn: Mrs Lee Siew Kuan/Ms Betty Ang)

Dear Sirs,

OFFER OF TENANCY FOR FLATTED FACTORY SPACE

1.   We are pleased to offer a tenancy of the Premises subject to the following
     covenants. terms and conditions in this letter and in the annexed
     Memorandum of Tenancy ("the Offer"):

     1.01 Location:

          Pte Lot A19597, Blk 1008 (the Building"), Toa Payoh North 403-09 to
          #03-18 Toa Payoh Industrial Estate Singapore 318996 ("the Premises')
          as delineated and edged ill red on the plan attached to the Offer.

     1.02 Term of Tenancy:

          3 years ("the Term") with effect from 01 January 2000 (the
          Commencement Date").

     1.03 Tenancy Agreement:

          Upon due acceptance of the Offer in accordance with clause 2 of this
          letter, you shall have entered into a tenancy agreement with US ("the
          Tenancy") and will be bound by the covenants, terms and conditions
          thereof.

          In the event of any inconsistency or conflict between any covenant,
          term or condition of this letter and the Memorandum of Tenancy, the
          relevant covenant, term or condition in this letter shall prevail.

     1.04 Area:

          Approximately 888.60 square metres (subject to survey).
<PAGE>

                                                                               2
                                                         Jurong Town Corporation

     1.05 Rent and Service Charge:

          (a)  Discounted rate of $12.03 per square metres for so long as the
               Tenant shall occupy by way of tenancy an aggregate floor am of
               not less than 1,000 square metres in the Building or in the
               various flatted factories belonging to the Landlord, and

          (b)  Normal rate of $12.40 per square metres with effect from the date
               the said aggregate floor area occupied is reduced to below 1,000
               square metres (ie. when the discount shall be totally withdrawn),

               ("Rent") to be paid without demand and in advance without
               deduction on the 1st day of each month of the year (i.e. 1st of
               January, February, Much, etc.). The next payment shall be made on
               01 February 1999.

          Service charge:

          $2.10 per square metre per month, ("Service Charge") as charges for
          services rendered by us, payable without demand on the same date and
          in the same manner as the Rent, subject to our revision from time to
          time.

     1.06 Security Deposit/Banker's Guarantee:

          You will at the time of acceptance of the Offer be required to place
          with us a deposit of $37,667.75 equivalent to 3 months' Rent (at the.
          discounted rate) and Service Charge ("Security Deposit") as security
          against any breach of the covenants, terms and conditions in the
          Tenancy.

          The Security Deposit may be in the form of cash and/or acceptable
          Banker's Guarantee in the form attached (effective from 01 November
          1999 to 30 June 2003) and/or such other form of security as we may in
          our absolute discretion permit or accept.

          The Security Deposit must be maintained at the same sum throughout the
          Term and shall be repayable to you without interest or returned to you
          for cancellation, after the termination of the Term (by expiry or
          otherwise) or expiry of the Banker's Guarantee, as the case may be,
          subject to appropriate deductions or payment to us for damages or
          other sums due under the Tenancy.

          If the Rent at the discounted rate is increased to the normal rate or
          Service Charge is increased or any deductions are made from the
          Security Deposit, you are to immediately pay the amount of such
          increase or make good the deductions so that the Security Deposit
          shall at all times be equal to 3 months' Rent and Service Charge.
<PAGE>

                                                                               3
                                                         Jurong Town Corporation

     1.07 Mode of Payment:

          Except for the payment to be made with your letter of acceptance
          pursuant to clause 2 of this letter, during the Term, you shall pay
          Rent, Service Charge and GST by Interbank GIRO or any other mode to be
          determined by us.

          Accordingly, you we to provide us with the duly completed GIRO
          authorization form enclosed herewith.

          However, pending firialisation for the CIRO arrangement, you shall pay
          Rent, Service Charge and GST as they fall due by cheque.

     1.08 Permitted Use:

          (a)  Subject to clause 1.12 of this letter, you shall commence full
               operations within four (4) months of the Commencement Date for
               the purpose of IC testing, services and packing for semi-
               conductor industry only and for no other purpose whatsoever (the
               Authorised Use").

          (b)  Thereafter, you shall maintain full and continuous operations
               and use and occupy the whole of the Premises for the Authorised
               Use.

          (c)  Subject to clauses (a) and (b) above, you shall use and occupy at
               least sixty percent (60%) of the gross floor area of the Premises
               for industrial activities and ancillary stores, and use and
               occupy the remaining gross floor area, if any, for off-ices,
               neutral areas, communal facilities and such other uses as may be
               approved in writing by us and the relevant governmental and
               statutory authorities PROVIDED THAT you shall not use and occupy
               the Premises for the purpose of commercial office and storage
               unrelated to the Authorised Use,

     1.09 Approvals

          The Tenancy is subject to approvals being obtained from the relevant
          government and statutory authorities.

     1.10 Possession of Premises:

          (a)  Keys to the Promises will be given to you two (2) months prior to
               the Commencement Date subject to due acceptance of the offer
               ("Possession Date").

          (b)  From the Possession Date until the Commencement Date, you shall
               be deemed a licensee upon the same terms and conditions in the
               Tenancy.
<PAGE>

                                                                               4
                                                         Jurong Town Corporation

          (c)  If you proceed with the Tenancy after the Commencement Date, the
               licence fee payable from the, Possession Date to the Commencement
               Date shall be waived ("Rent-Free Period"). Should you fail to so
               proceed, you shall:

               (i)   remove everything installed by you;
               (ii)  reinstate the Premises to its original state and condition;
                     and
               (iii) pay us a sum equal to the prevailing market rent payable
                     for the period from the Possession Date up to the date the
                     installations are removed and reinstatement completed to
                     our satisfaction,

               without prejudice to any other rights and remedies we may have
               against you under the Tenancy or at law.

     1.11 Preparation and Submission of Plans:
          (a)  No alteration, addition, improvement, erection, installation or
               interference to or in the Premises or the fixtures and fittings
               therein is permitted without Building Control Unit [BCU(JTC)]
               prior written consent. Your attention is drawn to clauses 2. 10
               to 2.19 and 2.34 of the Memorandum of Tenancy.

          (b)  You will be required to prepare and submit floor layout plans of
               your factory and plans of the air-conditioning works in
               accordance with the terms of the tenancy and the 'Guide'
               attached. It is important that you should proceed with the
               preparation and submission of the plans in accordance with the
               procedures set out in the said 'Guide'.

          (c)  Should there be alteration of existing automatic fire alarm and
               sprinkler system installation, alteration plans shall be
               submitted to Building Control Unit [BCU(JTC)] for approval on
               fire safety aspects. All air-conditioning, fire alarm & sprinkler
               system plans must be signed by a relevant Professional Engineer,
               registered with the Professional Engineers Board of Singapore.

          (d)  Upon due acceptance of the Offer, a copy of the floor and
               elevation plans (transparencies) will be issued to you to assist
               in the preparation of the plans required herein,

          (e)  No work shall commence until the plans have been approved by
               Building Control Unit [BCU(JTC)].

     1.12 Final inspection:
          You shall ensure that final inspection by us of all installations is
          carried out and our approval of the same is obtained before any
          operations in the Premises may be commenced.
<PAGE>

                                                                               5
                                                         Jurong Town Corporation

     1.13 Special Conditions:

          1    You shall comply and ensure compliance with the following
               restrictions:

               (a)  maximum loading capacity of the goods lifts in the Building;
                    and

               (b)  maximum floor loading capacity of 15.00 kiloNewtons per
                    square metre of the Premises on the 3rd storey of the
                    Building PROVIDED THAT any such permitted load shall be
                    evenly distributed.

               We shall not be liable for any loss or damage that you may suffer
               from any subsidence or cracking of the ground floor slabs and
               aprons of the Building.

          2    Option for renewal of tenancy
               -----------------------------

               (a)  You may within 3 months before the expiry of the Term make a
                    written request to us for a further term of tenancy.

               (b)  We may grant you a further term of tenancy of the Premises
                    upon mutual terms to be agreed between you and us subject to
                    the following:

                    (i)   there shall be no breach of your obligations at the
                          time you make your request for a further term;

                    (ii)  our determination of revised rent, having regard to
                          the market rent of the Premises at the time of
                          granting the further term, shall be final;

                    (iii) we shall have absolute discretion to determine such
                          covenants, terms and conditions, but excluding a
                          covenant for renewal of tenancy, and

                    (iv)  there shall not be any breach of your obligations at
                          the expiry of the Term.

     2.   Mode of Acceptance:

          The Offer shall lapse if we do not receive the following by 27 October
          1999:-

          .    Duly signed letter of acceptance (in duplicate) of all the
               covenants, terms and conditions in the Tenancy in the form
               enclosed at the Appendix. (Please date as required in the
               Appendix)

          .    Payment of the sum set out in clause 4.

          .    Duly completed GIRO authorization form.
<PAGE>

                                                                               6
                                                         Jurong Town Corporation

3.   Please note that payments made prior to your giving us the other items
     listed above may be cleared by and credited by us upon receipt- However, if
     the said other items are not forthcoming from you within the time
     stipulated herein, the Offer shall lapse and there shall be no contract
     between you and us arising hereunder. Any payments rcmived shall then be
     refunded to you without interest and you shall have no claim of whatsoever
     nature against us.

4.   The total amount payable is as follows:

<TABLE>
<CAPTION>

----------------------------------------------------------------------------------------------------------------------------------
                                                                       AMOUNT                                      +3 % GST
----------------------------------------------------------------------------------------------------------------------------------
<S>                                                                <C>                      <C>                    <C>
Rent:
----
Rent at $12.03 psm per month on 888.60
sqm for period 01 January 2000 to 31 January 2000                   $10,689.86
Less:
6.6% Property tax rebate on rental value
(01/07/1998 to 30/06/2000)                                          $   705.53
                                                                    ----------
                                                                    $ 9,984.33
----------------------------------------------------------------------------------------------------------------------------------
Service Charge:
--------------
Service Charge at $2.10 psm per month on 888.60 sqrn
for period 01 January 2000 to 31 January 2000                       $ 1,866.06              $11,850.39             $355.51
                                                                    ----------
----------------------------------------------------------------------------------------------------------------------------------
Deposit equivalent to three months' rcat
and service charge (or Banker's Guarantee
provided in accordance with sub- paragraph 1.06 above)                                      $37,667.75
----------------------------------------------------------------------------------------------------------------------------------
Stamp fee payable on Letter of Acceptane which will be
stamped by JTC on your behalf                                                               $ 1,198.00
----------------------------------------------------------------------------------------------------------------------------------
Sub-Total Payable                                                                           $50,716.14             $355.51
----------------------------------------------------------------------------------------------------------------------------------
Add: 3 % GST                                                                                $   355.51
                                                                                            ----------
----------------------------------------------------------------------------------------------------------------------------------
Total Amount Payable                                                                        $51,071.65
                                                                                            ==========
----------------------------------------------------------------------------------------------------------------------------------
</TABLE>
<PAGE>

5.   Rent-Free Period:

     As the Commencement Date will not be deferred, we advise you to accept the
     Offer as soon as possible and to collect the keys to the Premises on the
     scheduled date in order to maximize the Rent-free Period referred to in
     clause 1.10(c) of this letter.

6.   Variation to the Tenancy

     This letter and the Memorandtun of Tenancy constitute the full terms and
     conditions goveming the Offer and no terms or representation or otherwise,
     whether express or implied, shall form part of the Offer other thmi what is
     contained herein. Any variation, modification, amondment, deletion,
     addition or otherwise of the covenants, terms and conditions of the Offer
     shall not be enforceable unless agreed by both parties and reduced in
     writing by us.

7.   Car-Parldmg Scheme:

     (a) The car park for Blk 1008 is currently managed by a Tenants' Committee
     and you will:

         (i)  have to contribute towards all the operational and management
              costs, if any, incurred in connection with the car parks;

         (ii) observe and be bound by all the rules and regulations governing
              the uso and operation of the car park. A copy of the Tenant
              Committee's current rules and regulations is obtainable from the
                                                        ------------------

              Tenants' Committee. You are required to contact:

                      Ms Susan Ng
                      Wilson Parking (S) Pte Ltd
                      32 Sultan Centre
                      Singapore 198480
                      Tel No: 2966600

                      a member of the Committee on your use of the car park,

     (b) The Corporation shall not be liable -for any loss, damage, injury,
         liabilities, claim or action you may sustain or suft in the use of the
         car park and the tenants shall fully indemnify the Corporation against
         any loss, claims, penalties, demands, damage arising from the private
         management and operations of the car park by the tenants.

<PAGE>

                                                         Jurong Town Corporation

8.   Application for Approvals, Utilities etc.

          Upon your acceptance of the covenants, terms and conditions of the
          Offer, you are advised to proceed expeditiously as follows:

     8.01 Preliminary Clearance:

          Comply with the requirements of the Chief Engineer (Central Building
          Plan Unit), Pollution Control Department and/or other departments
          pursuant to your application/s for preliminary clearance. (Please note
          that we have referred your application to the relevant departmout/s)

     8.02 Discharge of Trade Effluence:

          Complete the attached Application for Permission to Discharge Trade
          Effluent into into Public Sewer and return the application form direct
          to the Head, Pollution Control Depaitment, Ministry of Environment
          Environment Building, 40 Scotts Road. Singapore 228231 (Telephone No.
          7327733).

     8.03 Electricity:

          Engage a registered electrical consultant or competent contractor to
          submit three sets of electrical single-line diagrams to and in
          accordance with the requirements of our Property Support Department
          (PSD), Customer Service Group, JTC East Zone Office for endorsement
          before an application is made to the Power Supply Pte Ltd to open an
          account for electricity connection. Please contact our Property
          Support Department (PSO) at Blk 25 Kallang Avenue #05-01 Kallang Basin
          Industrial Estate Singaporc 339416 direct for their requirements.

     8.04 Water:

          Submit four copies of sketch plans, prepared by a licensed plumber,
          showing the, section and layout of the plumbing, to our Building
          Control Unit [BCU(JTC)] for approval prior to the issue of a letter to
          Water Conservation Department, Public Utilities Board to assist you in
          your application for a water sub-meter.

     8.05 Telephone:

          Apply direct to Singapore Telecommunications Ltd for all connections.

<PAGE>

     8.06 Automatic Fire Alarm System (Incorporating Heat Detector)

          Engage a registered electrical consultant/professional engincer to
          submit two sets of fire alarm drawings, indicating the existing
          fixtures if any, the proposed modifications of the fire alarm and the
          layout of machinery, etc to and in accordance with the requirements of
          our Building Control Unit [BCU(JTC)]. Please contact our Building
          Control Unit [BCU(JTC)] at 301 Jurong Town Hall Road (3rd level)
          Singapore 609431 direct for further requirements.

     8.07 Factory Inspectorate

          Complete and return direct to Chief Inspector of Factories the
          attached form, "Particulars to be submitted by occupiers or Intending
          Occupiers of Factories".

Yours faithfully



By:/s/ Lai Get Luan

LAI GET LUAN (Ms)
MARKETING & SALES DEPARTMENT
INDUSTRIAL PARKS DEVELOPNENT GROUP
JURONG TOWN CORPORATION
Attd