UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC  20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR
15d-16 UNDER THE SECURITIES EXCHANGE ACT OF 1934

February 11, 2009

Commission File Number 1-10167

WESTPAC BANKING CORPORATION

(Translation of registrant’s name into English)

275 KENT STREET, SYDNEY, NEW SOUTH WALES 2000, AUSTRALIA

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F              x                           Form 40-F              o

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): o

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): o

Indicate by check mark whether the registrant by furnishing the information contained in this form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Act of 1934.

Yes         o                            No           x

If “Yes” is marked, indicate the file number assigned to the registrant in connection with Rule 12g3-2(b):82-

INCORPORATION BY REFERENCE

The information contained in this Form 6-K shall be incorporated by reference in the prospectus relating to the Registrant’s debt securities contained in the Registrant’s Registration Statement on Form F-3 (File No. 333-153500), as such prospectus may be amended or supplemented from time to time.

2

UNAUDITED PRO FORMA COMBINED FINANCIAL INFORMATION

On November 17, 2008 the Federal Court of Australia approved the share scheme for the merger of Westpac Banking Corporation (“Westpac”) and St.George Bank Limited (“St.George”). Pursuant to the share scheme, holders of St.George ordinary shares received 1.31 Westpac ordinary shares for each St.George ordinary share held on the record date, November 24, 2008.  In connection with the transaction, St.George SAINTS hybrid instruments were purchased by Westpac for A$100 per SAINTS security (plus accrued but unpaid dividends) and St.George award options were cancelled in exchange for Westpac ordinary shares.  St.George shareholders received a final dividend of A$0.94 cents per share for the year ended September 30, 2008 and, in connection with the merger, a special dividend of A$0.31 per share resulting in each St.George shareholder on the record date receiving dividends aggregating A$1.25 per St.George ordinary share.

The following unaudited pro forma combined balance sheet gives effect to the merger as if it occurred on September 30, 2008.  The accompanying unaudited pro forma combined income statement for the year ended September 30, 2008 gives effect to the merger as if it occurred on October 1, 2007. The unaudited pro forma combined financial information is derived from, and should be read in conjunction with, the historical consolidated financial statements of Westpac at and for the year ended September 30, 2008 which is included in Westpac’s Form 20-F for the year ended September 30, 2008 filed with the U.S Securities and Exchange Commission (the “SEC”) on November 6, 2008 (the “Form 20-F”) and the historical consolidated financial statements of St.George at and for the year ended September 30, 2008, which are included in Westpac’s Form 6-K filed on November 17, 2008.  The respective consolidated financial statements of Westpac and St.George were prepared in accordance with Australian equivalents to International Financial Reporting Standards (“A-IFRS”) and also comply with International Financial Reporting Standards (“IFRS”) as issued by the International Accounting Standards Board (“IASB”).

The unaudited pro forma combined financial information shows the impact of the merger of Westpac and St.George on the combined enterprise’s financial position and results of operations under the purchase method of accounting with Westpac treated as the acquirer. Adjustments have been prepared in accordance with the recognition and measurement principles of A-IFRS and IFRS.  Estimated adjustments have been made to reflect the purchase method of accounting as required by the A-IFRS accounting standard AASB 3: Business Combinations, including adjustments to record the assets and liabilities of St.George at their respective fair values.

AS OF THE DATE HEREOF, WESTPAC HAS NOT FINALIZED THE DETAILED VALUATION NECESSARY TO DETERMINE THE FAIR VALUE OF ASSETS AND LIABILITIES OF ST.GEORGE ACQUIRED BY WESTPAC.  CONSEQUENTLY, THESE ADJUSTMENTS REFLECT MANAGEMENT’S PRELIMINARY ESTIMATES OF FAIR VALUE NECESSARY TO PREPARE THE UNAUDITED PRO FORMA COMBINED FINANCIAL INFORMATION AND ARE BASED ON INFORMATION AVAILABLE AT THIS TIME.  THESE ALLOCATIONS WILL BE FINALIZED BASED ON VALUATION AND OTHER STUDIES TO BE COMPLETED.  THE ACTUAL ADJUSTMENTS MAY DIFFER

3

AS ADDITIONAL INFORMATION BECOMES AVAILABLE AND ADDITIONAL ANALYSIS IS PERFORMED BY MANAGEMENT. ACCORDINGLY, THE PURCHASE PRICE ALLOCATION ADJUSTMENTS AND RELATED IMPACTS ON THE UNAUDITED PRO FORMA COMBINED FINANCIAL INFORMATION ARE PRELIMINARY AND ARE SUBJECT TO REVISION, WHICH MAY BE MATERIAL, AFTER THE COMPLETION OF THE ALLOCATION.  The unaudited pro forma combined financial information is presented in an abbreviated form and therefore does not comply with all presentation and disclosure requirements of IFRS, and the requirements of A-IFRS applicable to annual financial reports prepared in accordance with the Corporations Act 2001 of Australia.

THIS UNAUDITED PRO FORMA COMBINED FINANCIAL INFORMATION IS FOR ILLUSTRATIVE INFORMATIONAL PURPOSES ONLY AND IS NOT NECESSARILY INDICATIVE OF THE RESULTS OF OPERATIONS THAT WOULD HAVE BEEN ACHIEVED HAD THE MERGER ACTUALLY TAKEN PLACE AT THE DATES INDICATED, AND DOES NOT PURPORT TO BE INDICATIVE OF THE FUTURE FINANCIAL POSITION OR OPERATING RESULTS. ACTUAL ADJUSTMENTS MAY DIFFER FROM THE PRO FORMA ADJUSTMENTS. In this regard, the unaudited pro forma combined financial information does not give effect to (i) any integration costs that may be incurred as a result of the merger, (ii) potential future operating costs and wholesale funding synergies, that may result from the merger, (iii) any allowance for revenue attrition or revenue opportunities that may be derived from the combined enterprise’s plans for growth, (iv) changes in estimates subsequent to the dates of such financial information, (v) restructuring charges that may be incurred to fully integrate and operate the combined enterprise more efficiently, or (vi) possible changes in the capital structure of the combined enterprise. FUTURE OPERATING RESULTS MAY DIFFER MATERIALLY FROM THE UNAUDITED PRO FORMA COMBINED FINANCIAL INFORMATION PRESENTED BELOW DUE TO VARIOUS FACTORS INCLUDING THOSE DESCRIBED UNDER THE CAPTIONS “RISK FACTORS”, AND “DISCLOSURE REGARDING FORWARD-LOOKING STATEMENTS” AND ELSEWHERE IN WESTPAC’S ANNUAL REPORT ON FORM 20-F.

In this Report on Form 6-K, all references to “A$” are to Australian dollars.

4

Unaudited pro forma combined income statement for the year ended September 30, 2008

Summary pro forma adjustments, which includes a description of each of the footnotes above, is an integral part of these statements

5

Unaudited pro forma combined balance sheet as at September 30, 2008

Summary pro forma adjustments, which includes a description of each of the footnotes above, is an integral part of these statements.

6

Notes to the Unaudited Pro Forma Combined Financial Information

1.                                      Basis of preparation

The unaudited pro forma combined financial information relating to the merger is presented as at and for the year ended September 30, 2008. The Reporting reclassification column represents the change in presentation of certain amounts in the historical consolidated financial statements of St.George to align with the presentation of Westpac and the preliminary presentation for the combined enterprise. For purposes of identifying the reclassification between line items on the unaudited pro forma combined balance sheet, letter references are provided, which are further explained below. These adjustments do not impact the unaudited pro forma combined income statement. The presentation of the combined enterprise’s financial statements will be completed by the time Westpac presents its March 31, 2009 interim financial report.

Following a review of accounting policies as disclosed in St.George’s audited financial statements for the year ended September 30, 2008, the accounting policies of St.George and Westpac are not considered to be materially different. Therefore, no adjustments have been made to the pro forma combined financial information to align accounting policies.

There were no material transactions or balances between Westpac and St.George requiring elimination in the unaudited pro forma combined income statement or balance sheet.

7

An analysis of the purchase consideration (including transaction costs) is presented below (in millions of Australian dollars, except for share and per share amounts):

Westpac paid the holders of the outstanding St.George SAINTS securities A$350 million, plus accrued but unpaid dividends, on the scheme implementation date December 1, 2008.  The purchase of SAINTS by Westpac occurred in conjunction with the share scheme and, as a result, adjustments have been made in the unaudited pro forma combined balance sheet presented above. On November 20, 2008, St.George confirmed its intention to redeem the remaining outstanding hybrid instruments, consisting of Stapled Preferred Securities (“SPS”), Converting Preference Shares I (“CPS I”) and Converting Preference Shares II (“CPS II”), for their face value plus accrued but unpaid dividends.  As a consequence, the SPS included in St.George’s balance sheet as part of shareholders’ equity have been reclassified and are presented as part of the combined enterprise’s liabilities.  CPS I and CPS II remain as liabilities of the combined enterprise.  For balances reclassified, the restated amount is the redemption amount, with differences to carrying value being included as part of goodwill.  No further adjustments to the St.George hybrid instruments have been reflected in the unaudited pro forma combined financial information as the timing and

8

terms of any redemption have not yet been finalized.  Differences in the pricing of any replacement instruments are not expected to be material to the unaudited pro forma combined financial statements and as a consequence have not been incorporated.

The merger will be accounted for using the purchase method of accounting requiring the fair value of the assets (including identified intangible assets) and liabilities of St.George to be determined as of the date of the acquisition November 17, 2008 and such currently estimated adjustments have been applied to the unaudited pro forma combined financial information as at September 30, 2008 and, where relevant, for the year ended September 30, 2008. Associated deferred tax assets and liabilities have also been recognized, where appropriate.  No deferred tax liability has been recognized for indefinite life intangible assets including brands.  The unaudited pro forma combined income statement reflects the reversal of deferred tax balances that were recognized as a consequence of the merger for the year ended September 30, 2008.  Upon redemption of the St.George hybrid instruments, St.George will join the Westpac tax consolidated group, which will result in the reset of the tax base of certain of St.George’s assets.  No adjustment has been made to estimate the reset tax base of St.George assets for the purposes of preparing the pro forma combined financial statements as the financial effect of joining the tax consolidated group has not been finalized.  When the reset tax bases are finalized, they may result in material adjustments to certain deferred tax balances recognized in the pro forma combined financial statements, with a corresponding adjustment to goodwill.  The excess of the consideration paid over St.George’s identifiable net assets acquired (after recognition of the adjustments noted above) has been allocated to goodwill.

Pursuant to A-IFRS, goodwill and certain indefinite-life intangible assets are not amortized. Instead, impairment tests are performed at least annually or more frequently if circumstances indicate an impairment event may have occurred. If impairment exists, the carrying amount of goodwill and certain indefinite-life intangible assets are immediately written down through a current charge to earnings. Accordingly, the goodwill and certain indefinite-life intangibles arising from the merger will be subject to an impairment test at least annually.  Goodwill reflects the anticipated benefits associated with the merger that is not attributable to any identifiable assets or liabilities acquired.  Goodwill that arises in a business combination is required to be attributed to the combined enterprise’s cash generating units based upon the synergistic benefits that have arisen from the acquisition.  A cash generating unit is a separate group of assets that generates cash flows independently of other parts of the business.  Westpac management has not finalized the allocation of goodwill to separate cash generating units.  This exercise will be completed by September 30, 2009.

All pro forma adjustments to the unaudited pro forma combined income statement are deemed to have recurring effects.  The individual pro forma adjustments are further described in the following footnotes.

The unaudited pro forma combined financial information includes estimated adjustments to record the assets and liabilities of St.George at their respective fair values and represents management’s best estimates based on information available at this time. The pro forma adjustments may be revised as additional information becomes available and additional analysis is performed. The income statement adjustments are derived from these estimates and are also subject to change.  The final allocation of the purchase price will be determined after completion of a final analysis to determine the fair values of St.George’s identifiable assets and liabilities as of the date of acquisition.  The final purchase accounting adjustments may be materially different from the pro forma adjustments presented in this document. Increases or decreases in the fair value of certain balance sheet amounts including, amongst other items, available for sale investments, loans, debt issues, loan capital, core deposit and other related intangible

9

assets will result in adjustments to the balance sheet and income statement. Such adjustments compared to the information shown in this document may change the amount of the purchase price allocated to goodwill and other assets and liabilities and may impact the income statement due to adjustments in yield and/or amortization of the adjusted assets or liabilities.

The pro forma adjustments described below include those that relate to reporting reclassifications, income statement and balance sheet adjustments to effect the merger.

2.                                      Reporting reclassifications

The pro forma adjustments that relate to reporting reclassifications in the unaudited pro forma combined balance sheet are as follows:

3.                                      Allocation of purchase consideration

The purchase consideration (including transaction costs) of A$12,165 million has been preliminarily allocated to the acquired net assets of St.George as follows:

10

4.                                      Summary pro forma adjustments

Unaudited pro forma combined income statement

The pro forma adjustments included in the unaudited pro forma combined income statement are as follows:

11

Unaudited pro forma combined balance sheet

The pro forma adjustments included in the unaudited pro forma combined balance sheet are as follows:

12

13

14

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

15