QuickLinks -- Click here to rapidly navigate through this document

Exhibit 10.28

ASSIGNMENT OF DEBT

THIS DEED is made on the 5th day of May 2005.

BETWEEN: CONTINENTAL GOLDFIELDS LIMITED (ACN 009 206 473) a company duly
incorporated in the state of Western Australia and having its registered office
at 945 Wellington Street, West Perth in the said State ("the Assignor").
AND:
VISTA GOLD CORP a corporation continued under the terms of the Yukon territory
and having its registered office at Suite 5, 7961 Shaffer Parkway, Littleton,
Colorado in the United States of America ("the Assignee").

In this Agreement, the Assignor and the Assignee shall be referred to jointly as
the "Parties" and individually as the "Party".

BACKGROUND

A.This Agreement relates to the debt between PT Masmindo DWI Area as the debtor
("Debtor") and the Assignee as the lender.

B.The debt owing by the Assignor to the Assignee on the date hereof is US $
27,948.00 inclusive of any applicable interest ("Outstanding Amount").

AGREEMENT

1.INTERPRETATION

1.1Definitions and Constructions.    In this Agreement unless the context
otherwise requires:

"Debt" means any and all receivables, rights, title and interests of the
Assignor over the Outstanding Amount and all rights and entitlements under the
debt, including but not limited to the right to receive repayment of the
Outstanding Amount and any other rights related thereto under any applicable
laws and regulations.

"Effective Date" means the date hereof.

2.ASSIGNMENT

2.1Assignment.    On the Effective Date, the Assignor hereby sells, assigns and
transfers to the Assignee free from all encumbrances the Debt and the Assignee
hereby purchases and accepts the assignment and transfer of the Debt from the
Assignor.

1

--------------------------------------------------------------------------------

2.2Assumption.    The Assignee hereby agrees, on the Effective Date, to assume
and be bound by the Assignor's obligations, duties and liabilities under the
Debt.

2.3Notice of Assignment.    To give effect to the sale, assignment and transfer
of the Assigned Rights under this Agreement to the Assignee, the Assignor shall
notify and obtain acknowledgment in writing from the Debtor in a form as set out
in Schedule of this Agreement.

2.4Payments.    As consideration for the assignment and sale as provided in
Clause 2 of this Agreement, the Assignee shall pay to the Assignor on the date
hereof the amount of US $1.00.

2.5Amounts after Effective Date.    Each of the Assignor and the Assignee hereby
agrees that if it receives any amount for the debt which is for the account of
the other Party, it shall receive the same for the account of such other Party
to the extent of such other Party's interest therein and shall promptly pay the
same to such other Party.

3.MISCELLANEOUS

3.1This Deed is governed by and construed in accordance with the laws of Western
Australia and the parties submit to the non-exclusive jurisdiction of its
courts.

3.2Any notice or communication given or made under this Assignment shall be in
writing and delivered or sent to the relevant party at its address or fax number
set out below (or such other address or fax number as the addressee has, by five
(5) Business Days prior written notice, specified to the other Patties):

The Assignor:        +618 9388 0676
The Assignee:        720-981-1186

Any notice or other communication delivered or sent in accordance with this
provision to the relevant party shall be deemed to have been delivered (a) if
hand delivered, when actually delivered to the relevant address; (b) if given or
sent by fax, when dispatched as evidenced by a transmission transcript.

3.3This Deed can be executed in counterparts and all counterparts taken together
shall form one and the same document.

2

--------------------------------------------------------------------------------

IN WITNESS the Parties have executed this deed on the date first written above.

THE COMMON SEAL OF CONTINENTAL
GOLDFIELDS LIMITED
(ACN 009 125 651)
was hereunto affixed by Order of the
Board of Directors in the presence of:    
/s/  PETER LANDAU      

--------------------------------------------------------------------------------

Secretary: Peter Landau
 
/s/  C.P. MOYTART      

--------------------------------------------------------------------------------

Director: C.P. Moytart
THE COMMON SEAL OF
VISTA GOLD CORP
was hereunto affixed by Order of the
Board of Directors in the presence of:
 
 
/s/  GREGORY G. MARLIER      

--------------------------------------------------------------------------------

Asst. Secretary: Gregory G. Marlier
 
/s/  M.B. RICHINGS      

--------------------------------------------------------------------------------

Director: M.B. Richings

3

--------------------------------------------------------------------------------

Schedule
Form Notice of Assignment

5 May 2005

PT MASMINDO DWI AREA
C/. JI. Widjaya No.8
Kebayoran Baru
Jakarta 12170
INDONESIA

Attention: President Director

Dear Sirs,

Re: NOTICE OF ASSIGNMENT

Reference is made to the Assignment of Debt dated 5 May 2005 between ourselves,
as the assignor ("Assignor") and Vista Gold Corp, as the assignee ("Assignee").

The Assignor hereby gives PT Masmindo DWI Area notice that the Assignor has
assigned all of its rights and benefits under the Deed dated 5 May 2005.

Accordingly, please regard the Assignee as being in a11 respect entitled to all
of our rights and benefits for the Debt and any outstanding amount thereunder,
and with effect from the Effective Date.

Any notice or other communication in connection with the Debt should be
addressed to:

VISTA GOLD CORP
Suite 5, 7961 Shaffer Parkway
Littleton, Colorado 80127
United States of America

Please acknowledge this Notice of Assignment in the space provided below and
return the original to us with a copy to the Assignee by facsimile
0011-1-720-981-1186.

4

--------------------------------------------------------------------------------

Upon signing of this Notice of Assignment you agree to release us from any
claims whatsoever that you may have against us in respect of the Debt.

Yours faithfully,
CONTINENTAL GOLDFIELDS LIMITED

Signed: /s/  PETER LANDAU      

--------------------------------------------------------------------------------

Name: Peter Landau
Title: Director/G. Sec.  

We acknowledge receipt of the above notice and agree to be bound by its terms:

PT MASMINDO DWI AREA

Signed: /s/  W. J. CROSSLEY      

--------------------------------------------------------------------------------

Name: William John Crossley
Title: President Director  

5

--------------------------------------------------------------------------------

QuickLinks

Exhibit 10.28