<PAGE>

                                                                    EXHIBIT 10.4

THIS WARRANT IS SUBJECT TO THE PROVISIONS OF AN INVESTORS' AGREEMENT, DATED AS
OF May 21, 1997, AND THIS WARRANT IS NOT ASSIGNABLE OR OTHERWISE TRANSFERABLE
EXCEPT IN ACCORDANCE WITH THE PROVISIONS OF SUCH INVESTORS' AGREEMENT (INCLUDING
PROVISIONS UNDER WHICH THE HOLDER HEREOF GRANTS A RIGHT OF FIRST REFUSAL ON THE
SALE OF THIS WARRANT), A COPY OF WHICH IS ON FILE WITH THE SECRETARY OF THE
ISSUER.  THE COMMON STOCK OR OTHER SECURITIES RECEIVABLE UPON EXERCISE HEREOF
ARE ALSO SUBJECT TO THE OWNERSHIP LIMITATIONS SET FORTH IN THE ISSUER'S ARTICLES
OF INCORPORATION.


THIS WARRANT AND THE COMMON STOCK OR OTHER SECURITIES RECEIVABLE UPON EXERCISE
HEREOF MAY NOT BE TRANSFERRED, SOLD, PLEDGED, HYPOTHECATED OR OTHERWISE DISPOSED
OF UNLESS (A)(i) SUCH DISPOSITION IS PURSUANT TO AN EFFECTIVE REGISTRATION
STATEMENT UNDER THE SECURITIES ACT OF 1933, (ii) THE HOLDER HEREOF SHALL HAVE
DELIVERED TO THE ISSUER AN OPINION OF COUNSEL, WHICH OPINION AND COUNSEL SHALL
BE SATISFACTORY TO THE ISSUER, TO THE EFFECT THAT SUCH DISPOSITION IS EXEMPT
FROM THE PROVISIONS OF SECTION 5 OF THAT ACT, OR (iii) A NO-ACTION LETTER FROM
THE SECURITIES AND EXCHANGE COMMISSION, SATISFACTORY TO COUNSEL FOR THE ISSUER,
SHALL HAVE BEEN OBTAINED WITH RESPECT TO SUCH DISPOSITION AND (B) SUCH
DISPOSITION IS PURSUANT TO REGISTRATION UNDER ANY APPLICABLE STATE SECURITIES
LAWS OR AN EXEMPTION THEREFROM.


No. 2                                                         New York, New York
                                                                    May 21, 1997

                               WESTFIELD AMERICA, INC.
                            COMMON STOCK PURCHASE WARRANT

         WESTFIELD AMERICA, INC., a Missouri corporation (the "COMPANY"),
hereby certifies that, for value received, PERPETUAL TRUSTEE COMPANY LIMITED
(the "WAT Trustee"), in its capacity as Trustee of Westfield America Trust
("WAT"), a public unit trust constituted under the laws of Australia


<PAGE>

pursuant to the Westfield America Trust Deed, dated March 28, 1996, as 
amended on May 9, 1996, is entitled, subject to the terms and conditions set 
forth below, (a) to purchase from the Company Two Million Eighty-nine 
Thousand Five Hundred Fifty-two (2,089,552)(1) duly authorized, validly 
issued, fully paid and nonassessable shares of common stock, par value $.01 
per share, of the Company, (the "COMMON STOCK") at a purchase price per share 
of $[     ](2) (as adjusted from time to time, the "EXERCISE PRICE"), at any 
time or from time to time on or after the date hereof and (b) to exercise the 
other rights set forth herein.  The number and character of such shares of 
Common Stock and the Exercise Price are subject to adjustment as provided 
herein.

         I.    EXERCISE OF WARRANT.  This Warrant may be exercised at any time
and from time to time on or after the date hereof and prior to May 21, 2017 (the
"EXPIRATION DATE") by the holder hereof, in whole or in part, on any business
day by:

         A.   the presentation of this Warrant, together with a duly executed
    copy of the Exercise Form attached hereto as Exhibit A and the other
    documentation set forth therein, to the Secretary of the Company at its
    principal offices, upon which presentation the Secretary of the Company
    shall make appropriate notations in the stock transfer records (and other
    records, as appropriate) of the Company indicating the number of shares of
    Common Stock issued pursuant to such exercise and the number of shares of
    Common Stock, if any, into which the Warrant thereafter shall remain
    exercisable; and
--------------------

1.  This number will be equal to $43 million divided by the initial price to
    public per share of Common Stock issued in the Company's initial public 
    offering of Common Stock (the "IPO").

2.  This number will be equal to the initial price to public per share of 
    Common Stock issued in the IPO.


                                          2

<PAGE>

         B.   the payment, by wire transfer of immediately available funds or
    certified or official bank check payable to the order of the Company of an
    amount equal to the amount obtained by multiplying (i) the number of
    shares of Common Stock designated in such Exercise Form by (ii) the
    Exercise Price.

This Warrant shall expire on the Expiration Date.

         II.   CERTIFICATES FOR SHARES OF COMMON STOCK.  As soon as practicable
after the proper exercise of this Warrant in whole or in part, and in any event
within 30 days thereafter, the Company will cause to be issued in the name of
and delivered to the holder hereof:

         (a)  a certificate or certificates for the number of duly authorized,
    validly issued, fully paid and nonassessable shares of Common Stock to
    which the holder hereof shall be entitled upon such exercise;

         (b)  in case such exercise is in part only, a new Warrant of like
    tenor, calling on its face for the number of shares of Common Stock equal
    to the number of such shares called for on the face of this Warrant minus
    the number of such shares designated by the holder hereof upon such
    exercise as provided in Section 1 hereof.

         III.  RESERVATION OF SHARES OF COMMON STOCK.  The Company covenants
that it will at all times keep available such number of authorized shares of its
Common Stock issuable upon exercise of the Warrant, which will be sufficient to
permit the exercise of the Warrant for the full number of shares of Common Stock
into which the Warrant is exercisable during the exercise period specified
herein.  The Company further covenants that such shares of Common Stock, when
issued pursuant to the exercise of this Warrant, will be duly and validly
issued, fully paid and nonassessable.


                                          3

<PAGE>

         IV.   ADJUSTMENT OF NUMBER OF SHARES OF COMMON STOCK.  The number and
kind of securities purchasable upon exercise of the Warrant shall be subject to
adjustment from time to time as follows:

         A.  SUBDIVISIONS, COMBINATIONS AND OTHER ISSUANCES.  If the Company
    shall at any time prior to the Expiration Date subdivide its Common Stock
    by stock split or otherwise, or combine its capital stock by reverse stock
    split or otherwise, or issue additional securities as a dividend with
    respect to any shares of its Common Stock, as the case may be, the number
    of shares of Common Stock issuable on the exercise of this Warrant shall
    forthwith be proportionately increased and the Exercise Price shall be
    proportionately decreased in the case of a subdivision or stock dividend,
    and the number of shares of Common Stock issuable on the exercise of this
    Warrant shall forthwith be proportionately decreased and the Exercise Price
    shall be proportionately increased in the case of a combination.  Any
    adjustment under this Section 4(a) shall become effective at the close of
    business on the date the subdivision or combination becomes effective, or
    as of the record date of such dividend, or in the event that no record date
    is fixed, upon the payment of such dividend.

         B.  RECONSTRUCTION.  If prior to the Expiration Date, the Company
    effects a capital reconstruction (other than a subdivision, combination or
    stock dividend covered by paragraph (a) above), merger, consolidation or
    any return of capital or other capital distribution, except for periodic
    distributions made pro-rata among the shareholders of a class of stock or
    units which are not in redemption of any shares of Common Stock, or any
    similar capital transaction that would affect the capital structure of the
    Company, excluding any payment of an ordinary cash dividend in respect of
    the operations of the Company, then in such event (i) the number of shares
    of Common Stock issuable


                                          4

<PAGE>

    upon exercise hereof, (ii) the Exercise Price, or (iii) some or all of such
    factors, will be adjusted, as appropriate, in a manner (x) approved by the
    Company and the holder hereof and (y) which is fair and equitable to the
    holder hereof and the holders of Common Stock.

         C.  MERGERS, ETC.  If prior to the Expiration Date, the Company shall
    be merged or consolidated into a new entity or if the Company shall
    transfer all or substantially all of its assets to another entity, then
    upon a subsequent exercise of this Warrant, the holder hereof shall be
    entitled to receive securities in the new transferee entity equal to what
    the holder hereof would have received had it exercised this Warrant and
    owned shares of Common Stock immediately prior to such transaction.

         D.  NOTICE OF ADJUSTMENT.  When any adjustment is required to be made
    in the number or kind of shares purchasable upon exercise of this Warrant,
    the Company promptly shall notify the holder of this Warrant of such event
    and of the number of shares and the type of securities or property
    thereafter purchasable upon exercise of this Warrant.

         E.  DISPUTES.  If a dispute arises between the Company and the holder
    hereof in relation to an adjustment to:  (i) the number of shares of
    Common Stock issuable upon exercise hereof, (ii) the Exercise Price, or 
    (iii) some or all of such factors, to be made pursuant to this Section 4,
    either party is entitled to refer the dispute (but no other dispute) to an
    Expert.  "EXPERT" means an independent, international investment banking
    firm agreed to by the Company and the holder hereof, or (in default of
    agreement), an independent, international investment banking firm nominated
    (at the request of any party) by the President or the head for the time
    being of the Australian Institute of Chartered Accountants.  The Expert
    must:  (1) resolve the dispute


                                          5

<PAGE>

    in a timely manner as an expert and not as an arbitrator, and (2) determine
    the party or parties responsible for paying the costs of the Expert having
    regard to his findings concerning resolution of the dispute, provided that
    the holder hereof will not bear any expense in excess of its pro rata
    interest in the Company.

         V.    NO FRACTIONAL SHARES OR SCRIP.  No fractional shares or scrip
representing fractional shares shall be issued upon the exercise of this
Warrant, but in lieu of such fractional shares the Company shall make a cash
payment therefor on the basis of the exercise price then in effect with respect
to this Warrant.

         VI.   RESTRICTIONS ON TRANSFER AND EXERCISABILITY.  (a) This Warrant
shall be subject to certain limited restrictions on transferability (including a
right of first refusal) set forth in the Investors' Agreement, dated as of May
[    ], 1997, among the Company, the original holder of this Warrant and certain
other parties, a copy of which shall be furnished without charge to the holder
hereof upon request.  In addition, the shares of Common Stock or other
securities receivable upon exercise hereof are subject to the ownership
limitations set forth in the Company's articles of incorporation.

         (b)  Neither this Warrant nor the Common Stock issuable upon exercise
hereof may be transferred, sold, pledged, hypothecated or otherwise disposed of,
and this Warrant may not be exercised, unless (A) such disposition or exercise
is pursuant to an effective registration statement under the Securities Act, (B)
the holder hereof shall have delivered to the Company an opinion of counsel,
which opinion and counsel shall be satisfactory to the Company, to the effect
that such disposition or exercise is exempt from the provisions of Section 5 of
the Securities Act, (C) a no-action letter from the Securities and Exchange
Commission, satisfactory to counsel for the Company, shall have been obtained
with respect to such disposition or exercise, or (D) the Warrant or Common Stock
is being exercised by (or


                                          6

<PAGE>

transferred to) the WAT Trustee, the manager of WAT or any of its affiliates.

         (c)  Each Warrant certificate shall bear the legend set forth on the
first page of this certificate.

         (d)  Any certificates representing Common Stock issued upon exercise
hereof shall bear the following legends:

    THE SECURITIES REPRESENTED BY THIS CERTIFICATE MAY NOT BE TRANSFERRED,
    SOLD, PLEDGED, HYPOTHECATED OR OTHERWISE DISPOSED OF UNLESS (A) (i)
    SUCH DISPOSITION IS PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT
    UNDER THE SECURITIES ACT OF 1933, (ii) THE HOLDER HEREOF SHALL HAVE
    DELIVERED TO THE ISSUER AN OPINION OF COUNSEL, WHICH OPINION AND
    COUNSEL SHALL BE SATISFACTORY TO THE ISSUER, TO THE EFFECT THAT SUCH
    DISPOSITION IS EXEMPT FROM THE PROVISIONS OF SECTION 5 OF THAT ACT, OR
    (iii) A NO-ACTION LETTER FROM THE SECURITIES AND EXCHANGE COMMISSION,
    SATISFACTORY TO COUNSEL FOR THE ISSUER, SHALL HAVE BEEN OBTAINED WITH
    RESPECT TO SUCH DISPOSITION AND (B) SUCH DISPOSITION IS PURSUANT TO
    REGISTRATION UNDER ANY APPLICABLE STATE SECURITIES LAWS OR AN
    EXEMPTION THEREFROM.

    THE SHARES OF COMMON STOCK REPRESENTED BY THIS CERTIFICATE ARE SUBJECT
    TO RESTRICTIONS ON OWNERSHIP AND TRANSFER FOR THE PURPOSE OF THE
    ISSUER'S MAINTENANCE OF ITS STATUS AS A REAL ESTATE INVESTMENT TRUST
    UNDER THE INTERNAL REVENUE CODE OF 1986, AS AMENDED (THE "CODE").  NO
    INDIVIDUAL MAY BENEFICIALLY OWN COMMON SHARES IN EXCESS OF THE THEN
    APPLICABLE OWNERSHIP LIMIT WITH RESPECT TO COMMON SHARES, WHICH MAY
    DECREASE OR INCREASE FROM TIME TO TIME, UNLESS SUCH INDIVIDUAL IS AN
    EXISTING HOLDER.  ANY INDIVIDUAL WHO ATTEMPTS TO BENEFICIALLY OWN
    SHARES IN EXCESS OF THE ABOVE LIMITATION MUST IMMEDIATELY NOTIFY THE
    COMPANY.  ALL


                                          7

<PAGE>

    TERMS USED IN THIS LEGEND WITHOUT DEFINITION HAVE THE MEANINGS DEFINED IN
    THE ISSUER'S ARTICLES OF INCORPORATION, AS THE SAME MAY BE FURTHER AMENDED
    FROM TIME TO TIME, A COPY OF WHICH, INCLUDING THE RESTRICTIONS ON OWNERSHIP
    AND TRANSFER, WILL BE SENT WITHOUT CHARGE TO EACH SHAREHOLDER WHO SO
    REQUESTS.  IF THE RESTRICTIONS ON OWNERSHIP AND TRANSFER ARE VIOLATED, THE
    COMMON SHARES REPRESENTED HEREBY WILL BE AUTOMATICALLY EXCHANGED FOR EXCESS
    SHARES AND WILL BE DEEMED TRANSFERRED TO A SPECIAL TRUST AS PROVIDED IN THE
    ARTICLES OF INCORPORATION.

    THIS SECURITY IS ISSUED PURSUANT TO AND IS SUBJECT TO THE TERMS AND
    CONDITIONS OF THE ISSUER'S ARTICLES OF INCORPORATION, AS AMENDED,
    LIMITING THE NUMBER OF HOLDERS OF RECORD OF THE ISSUER'S COMMON STOCK.

         VII.  SUCCESSORS AND ASSIGNS.  The terms and provisions of this
Warrant shall inure to the benefit of, and be binding upon, the Company and the
holders hereof and their respective successors and assigns.

         VIII. AMENDMENTS.  This Warrant may not be supplemented, amended
or otherwise modified without the prior written consent of the Company and the
holder hereof.  Any such amendment shall be binding upon each subsequent holder
of this Warrant.

         IX.   GOVERNING LAW.  This Warrant shall be governed by the laws of
the State of New York as applied to


                                          8

<PAGE>

agreements among New York residents made and to be performed entirely within the
State of New York.


                                       WESTFIELD AMERICA, INC.



                                       By:  /s/ Mark Stefanek
                                          -------------------------------
                                          Name:  Mark Stefanek
                                          Title: Chief Financial Officer &
                                                 Treasurer



                                          9

<PAGE>

                                                                       EXHIBIT A




                                    EXERCISE FORM
                      (To be executed upon exercise of Warrant)


         The undersigned hereby irrevocably elects to exercise the right,
represented by the attached Warrant, to purchase __________ shares of Common
Stock of Westfield America, Inc. (the "COMPANY"), par value $.01 per share 
("COMMON STOCK"), as provided for in the Warrant Certificate and herewith 
tenders in payment for such shares of Common Stock payment of the purchase 
price in full in the form of cash or a check payable to the order of the 
Company in the amount of $_______, all in accordance with the terms of the 
Warrant Certificate.  The undersigned requests that a certificate for such 
shares of Common Stock be registered in the name of ______________________, 
whose address is _______________________________________, and that such 
certificate shall be delivered to _______________________________ at the 
following address: ________________________________________________________.


         The undersigned hereby acknowledges and agrees:

         (a) the undersigned has read the restrictions on exercise and on
transferability set forth in the Warrant Certificate and in the Company's
articles of incorporation. The undersigned is acquiring the Common Stock for its
own account and not with a view to, or for sale in connection with, any
distribution thereof that would violate or require registration under any U.S.
federal or state securities or "Blue Sky" laws.  The undersigned understands
that the Common Stock has not been, and will not be, registered under the U.S.
Securities Act of 1933, as amended (the "SECURITIES ACT"), may not be offered
or sold except as permitted by the Warrant Certificate and shall be required to
bear a legend as set forth in the Warrant Certificate and in the Company's
articles of incorporation.  The undersigned agrees, on its own behalf and on
behalf of any account[s] for which the undersigned is acting as hereinafter
stated, that if the


                                          10

<PAGE>

undersigned should reoffer, resell, pledge or transfer any Common Stock, the
undersigned will do so only in accordance with the Warrant Certificate; and

         (b) APPLICABLE PARAGRAPH TO BE INSERTED

NOTE 1:  the following paragraph to be included in a notice of exercise by the
trustee of Westfield America Trust ("WAT EXERCISE"):

[The undersigned is the trustee of Westfield America Trust, an Australian
trust].

NOTE 2:  the following paragraph to be included in a notice of exercise other
than a WAT Exercise:

[We are delivering herewith [a written opinion of a nationally recognized United
States counsel, which opinion and counsel shall be satisfactory to the Company,]
[a no-action letter from the Securities and Exchange Commission, satisfactory to
counsel to the Company] to the effect that the offer of the Common Stock to and
the purchase of the Common Stock by the undersigned is exempt from registration
under the Securities Act.]


Dated:  ______________________


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


                                  By:  /s/ Mark Stefanek
                                     -------------------------------
                                     Name:  Mark Stefanek
                                     Title: Chief Financial Officer 
                                            Treasurer


                                          11