# **Exhibit 12**

# ** **

# **CERTIFICATION**

# ** **

I, Gail Patricia Kelly, certify that:

 

1.                           I have reviewed thisannual report on Form 20-F of Westpac Banking Corporation (“the company”);

 

2.                           Based on myknowledge, this report does not contain any untrue statement of a material factor omit to state a material fact necessary to make the statements made, inlight of the circumstances under which such statements were made, notmisleading with respect to the period covered by this report;

 

3.                           Based on myknowledge, the financial statements, and other financial information includedin this report, fairly present in all material respects the financialcondition, results of operations and cash flows of the company as of, and for,the periods presented in this report;

 

4.                           The company’s othercertifying officer and I are responsible for establishing and maintainingdisclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and15d-15(e)) and internal control over financial reporting (as defined inExchange Act Rules 13a-15(f) and 15d-15(f)) for the company and have:

 

(a)          Designed such disclosure controls andprocedures, or caused such disclosure controls and procedures to be designedunder our supervision, to ensure that material information relating to the company,including its consolidated subsidiaries, is made known to us by others withinthose entities, particularly during the period in which this report is beingprepared;

 

(b)         Designed such internal control over financialreporting, or caused such internal control over financial reporting to bedesigned under our supervision, to provide reasonable assurance regarding thereliability of financial reporting and the preparation of financial statementsfor external purposes in accordance with generally accepted accountingprinciples;

 

(c)  Evaluated the effectiveness of the company’sdisclosure controls and procedures and presented in this report our conclusionsabout the effectiveness of the disclosure controls and procedures, as of theend of the period covered by this report based on such evaluation; and

 

(d)         Disclosed in this report any change in the company’sinternal control over financial reporting that occurred during the periodcovered by the annual report that has materially affected, or is reasonablylikely to materially affect, the company’s internal control over financialreporting; and

 

5.               The company’s othercertifying officer and I have disclosed, based on our most recent evaluation ofinternal control over financial reporting, to the company’s auditors and theaudit committee of the company’s board of directors (or persons performing theequivalent functions):

 

(a)          All significant deficiencies and materialweaknesses in the design or operation of internal control over financialreporting which are reasonably likely to adversely affect the company’s abilityto record, process, summarize and report financial information; and

 

(b)         Any fraud, whether or not material, thatinvolves management or other employees who have a significant role in the company’sinternal control over financial reporting.

 
| Date: 4  November 2009                    |   |
|------------------------------------------------|--------|
|                                           |   |
|                                           |   |
| /s/ Gail  Patricia Kelly                       |   |
|                                           |   |
|                                           |   |
| Managing  Director and Chief Executive Officer |   |

 

----

# ** **

# **CERTIFICATION**

# ** **

I, Philip Matthew Coffey, certify that:

 

1.                           I have reviewed thisannual report on Form 20-F of Westpac Banking Corporation (“the company”);

 

2.                           Based on myknowledge, this report does not contain any untrue statement of a material factor omit to state a material fact necessary to make the statements made, inlight of the circumstances under which such statements were made, notmisleading with respect to the period covered by this report;

 

3.                           Based on myknowledge, the financial statements, and other financial information includedin this report, fairly present in all material respects the financialcondition, results of operations and cash flows of the company as of, and for,the periods presented in this report;

 

4.                           The company’s othercertifying officer and I are responsible for establishing and maintainingdisclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and15d-15(e)) and internal control over financial reporting (as defined inExchange Act Rules 13a-15(f) and 15d-15(f)) for the company and have:

 

(a)          Designed such disclosure controls andprocedures, or caused such disclosure controls and procedures to be designedunder our supervision, to ensure that material information relating to the company,including its consolidated subsidiaries, is made known to us by others withinthose entities, particularly during the period in which this report is beingprepared;

 

(b)         Designed such internal control over financialreporting, or caused such internal control over financial reporting to bedesigned under our supervision, to provide reasonable assurance regarding thereliability of financial reporting and the preparation of financial statementsfor external purposes in accordance with generally accepted accountingprinciples;

 

(c)          Evaluated the effectiveness of the company’sdisclosure controls and procedures and presented in this report our conclusionsabout the effectiveness of the disclosure controls and procedures, as of theend of the period covered by this report based on such evaluation; and

 

(d)         Disclosed in this report any change in the company’sinternal control over financial reporting that occurred during the periodcovered by the annual report that has materially affected, or is reasonablylikely to materially affect, the company’s internal control over financialreporting; and

 

5.               The company’s othercertifying officer and I have disclosed, based on our most recent evaluation ofinternal control over financial reporting, to the company’s auditors and theaudit committee of the company’s board of directors (or persons performing theequivalent functions):

 

(a)          All significant deficiencies and materialweaknesses in the design or operation of internal control over financialreporting which are reasonably likely to adversely affect the company’s abilityto record, process, summarize and report financial information; and

 

(b)         Any fraud, whether or not material, thatinvolves management or other employees who have a significant role in the company’sinternal control over financial reporting.

 
| Date:  4 November 2009 |   |
|----------------------------------|--------|
|                             |   |
|                             |   |
| /s/ Philip  Matthew Coffey       |   |
|                             |   |
|                             |   |
| Chief  Financial Officer         |   |

 

----