<PAGE>

                                                                   EXHIBIT 10.15

            TRIO-TECH
            ---------
          INTERNATIONAL

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 1004 TOA PAYOH NORTH #01-
08 TO #01-15 TOA PAYOH INDUSTRIAL ESTATE SINGAPORE 318995

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 $12,499.07 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 PTD LTD

In the presence of :

                                 By: /s/ Betty Ang

---------------------------------------------------------------------------
Name of witness               :  Miss Betty Ang
NRIC No.                      :  S6945849A
<PAGE>

                                                   DID :5688574
                                                   FAX: 5688593
                                                   Email: getluan@jtc.gov.sg


19 November, 1999

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




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

Dear Sirs

AMENDMENT TO LETTER OF OFFER OF TENANCY IN RESPECT OF THE PREMISES AT BLK 1004
TOA PAYOH NORTH #01-08 TO #01-15 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 $16.30 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>

    (b) Normal rate of $16.80 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,
        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 $35,201.04 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>

                                             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 $16.30 psm per month on 637.70
     sqrn for period 16 January 2000 to
     15 February 2000                                               $10,394.51

     Less:
     ----

     6.6% Property tax rebate on rental value
     (01/07/1998 to 30/06/2000)                                     $   686.04
                                                                    ----------
                                                                    $ 9,708.47

     -------------------------------------------------------------------------------------------------------------
     Service Charge:
     --------------

     Service Charge at $2.10 psm per month
     on 637.70 sqrn for period
     16 January 2000 to 15 February 2000                            $ 1,339.17        $11,047.64           $331.43
                                                                    ----------
     -------------------------------------------------------------------------------------------------------------
     Deposit equivalent to three months' rent
     and service charge (or Banker's Guarantee
     provided in accordance with sub-paragraph
     1.06 above)                                                                      $35,201.04
     -------------------------------------------------------------------------------------------------------------
     Stamp fee payable on Letter of Acceptane
     which will be stamped by JTC on your
     Behalf                                                                           $ 1,120.00
     -------------------------------------------------------------------------------------------------------------
               Sub-Total Payable                                                      $47,368.68           $331.43
     -------------------------------------------------------------------------------------------------------------
     Add: 3 % GST                                                                     $   331.43
                                                                                      ----------
     -------------------------------------------------------------------------------------------------------------
     Total Amount Payable                                                             $47,700.11
                                                                                      ----------
     -------------------------------------------------------------------------------------------------------------
</TABLE>
<PAGE>

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

5    Please let us have letter of offer dated remittance amounting to $12,499.07
     together with your letter of 13 October 1999 and $47,700.11. a Banker's
     Guarantee in acceptance of the the above amendments (Alternatively, you may
     lieu of the cash deposit terms and conditions together with your wish to
     produce a cheque of of $35,201.04) by 22 stipulated in our 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>

                                                       DID: 5688574
                                                       FAX: 5688593
                                                       Email: getluan@jtc.gov.sg


13 October 1999

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,

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 A455 1 (i), Blk 1004 ("the Building"), Toa. Payoh North #01 -
           08 to #01-15 Toa Payoh Industrial Estate Singapore 318995 ("the
           Premises") as delineated and edged in red on the plan attached to the
           Offer.

     1.02  Term of Tenancy;

           3 -years ("the Term") with effect from of 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 of condition of this letter and the Memorandum of Tenancy, the
           relevant covenant, term or condition in this letter shall prevail.

     1.04  Area:

           Approximately 637.70 square metres (subject to survey).
<PAGE>

                                                         Jurong Town Corporation

1.05  Rent and Service Charge.

      (a)  Discounted rate of $16.30 per square metres for so long as the Tenant
           shall occupy by way of tenancy an aggregate floor area of not less
           thin 1,000 square metres in the Building or in the various flatted
           factories belonging to the Landlord, and

      (b)  Normal rate of $16.80 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 mouth of the you (i.e. 1st of January,
           February, March, 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 $35,201.04 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 0 November 1999 to 30 June
      2003) and/or such other form of security as we may in our absolute
      discretion 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 a Security Deposit shall at all times be
      equal to 3 months' Rent and Service Charge.
<PAGE>

                                                         Jurong Town Corporation

1.07  Mode of Payment:

      You have an existing account with us from which we will deduct the
      aforesaid payments. You are therefore not required to submit a duly
      completed GIRO form as part of the Mode of Acceptance herein unless you
      wish to have a separate GIRO account to meet the aforesaid payments.

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 design and assembly of printed circuit boards and burn-in
           test equipment 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 offices, 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 Premises 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>

                                                        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(PTC)] 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>

                                                      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 12.50 kiloNewtons per
                      square metre of the Premises on the 1st 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 November 1999:-

     .  Duly signed letter of acceptance (ie. 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 (if any).
<PAGE>

                                                         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 the shall be no contract
     between you and us arising hereunder. Any payments received shall then be
     refunded to you without interest and you shall have no claim of whatsoever
     nature against.

4    The total amount payable is as follows:

<TABLE>
<CAPTION>
     ----------------------------------------------------------------------------------------------------------
                                                                   AMOUNT                              +3 % GST
     ----------------------------------------------------------------------------------------------------------
     <S>                                                         <C>              <C>                  <C>
     Rent:
     ----
     Rent at $16.30 psm. per month on 637.70
     sqm for period 01 January 2000 to
     31 January 2000                                             $10,394.51

     Less:
     ----
     6.6% Property tax rebate on rental value
     (01/07/1998 to 30ID6/2000)                                  $   686.04
                                                                 ----------
                                                                 $ 9,708.47
     ----------------------------------------------------------------------------------------------------------
     Service Charge:
     --------------
     Service Charge at $2.10 psm per month
     on 637.70 sqm for period
     01 January 2000 to 31 January 2000                          $ 1,339.17       $11,047.64            $331.43
                                                                 ----------
     ----------------------------------------------------------------------------------------------------------
     Deposit equivalent to three months' rent
     and service charge (or Banker's Guarantee
     provided in accordance with sub-
     paragraph 1.06 above)                                                        $35,201.04
     ----------------------------------------------------------------------------------------------------------
     Stamp fee payable on Letter of Acceptance
     which will be stamped by JTC on your
     Behalf                                                                       $ 1,118.00
     ----------------------------------------------------------------------------------------------------------

         Sub-Total Payable                                                        $47,366.68            $331.43
     ----------------------------------------------------------------------------------------------------------
     Add: 3 % GST                                                                 $   331.43
                                                                                  ----------
     ----------------------------------------------------------------------------------------------------------

     Total Amount Payable                                                         $47,698.11
     ----------------------------------------------------------------------------------------------------------
</TABLE>
<PAGE>

                                                         Jurong Town Corporation

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 Memorandum of Tenancy constitute the full tenancy and
     conditions governing the Offer and no terms or representation or otherwise,
     whether express or implied, shall form part of the Offer other than what is
     contained herein. Any variation, modification, amendment 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-Parking Scheme:

     (a)  The car park for Blk 1004 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 use 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 Contra
                    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 suffer 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 department/s).

     8.02 Discharge of Trade Effluence:

          Complete the attached Application for Permission to Discharge Trade
          Effluent into Public Sewer and return the application form direct to
          the Head, Pollution Control Department, 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 Services 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 (PSD) at Blk 25 Kallang Avenue #05-01 Kallang Basin
          Industrial Estate Singapore 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 Beat Detector)

          Engage a registered electrical coa5ultanVprofessional engineer 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 DEVELOPMENT GROUP
JURONG TOWN CORPORATION
Attd