Collary, who is returning to Australia after a four year spell at the Bank of Montreal in Canada, will not take up his new post until later this year,

His appointment comes at a time of operational upheaval at Westpac. Several executives have left in recent months as the bank deals with the effects of a money laundering scandal that broke late last yeat and continues to rumble on.

Chief financial officer and former head of innovation Gary Thursby announced he would be leaving early next year. This follows the resignation of CIO Craig Bright, which was announced in May and will take effect in September. Thursby will then take temporary charge of the bank's operations until Collary's arrival.

According to Westpac chief executive Peter King, who worked with Collary during their time at Citi in North America, the new appointee Collary has "a proven track record of delivering large-scale transformation programs at major international banks that improve operating and technology performance".

Collary will be in charge of 7,000 staff in the newly consolidated technology and operations unit that will be expected to produce some cost savings and also greater operational efficiency as the bank looks to recover from last year's money laundering case.

In June the bank blamed technology and human error rather than intentional wrong-doing for the AML errors which could well be more extensive than first thought. Just this week Westpac issued a market update, stating that it had found a further 375,000 transactions which were inaccurately reported to regulator Austrac, more than double the number that was disclosed back in May.

King said that the merger of technology and operations "will help us to continue to drive our technology transformation agenda and accelerate work on simplifying our processes". 

In theory, the consolidation will create closer links between the bank's software developers and the management of its data and call centres as well as its loan processing units. However, much of this will be dependant on the successful integration of the bank's various core banking units and legacy systems, some of which have been inherited from earlier mergers.