NAB executives should be obsessed with working for customers, interim chief executive Phil Chronican said as he promised change at the scandal-hit lender.

Mr Chronican started in his post on Friday following the abrupt resignation of his predecessor Andrew Thorburn, who was last month criticised in the financial services royal commission's final report.

In an internal email sent to the bank's 100 most senior executives on Thursday, Mr Chronican said he agreed with the Royal Commission's finding that NAB was not meeting the expectations of its key stakeholders.

"We are the bank's most senior leaders: we need to run the bank - and we need to change it," wrote Chronican, who was a non-executive director on the NAB board when tapped for the interim role.

"We need to bring the same obsession to customer outcomes that airline companies do to safety."

His first day in the top job coincided with the arrest of a former supplier accused of defrauding NAB of millions of dollars.

NAB said it was cooperating with police, with the alleged fraud involving a former staff member.

"If the alleged fraud is proven, it represents a most serious breach of trust by a former employee," the bank said in a statement on its website.

During the royal commission, the bank admitted its subsidiaries wrongly charged fees to thousands of customers without providing them with services.

In his email to executives, Chronican also said the bank was focused on ensuring fair compensation to customers for its wrongdoing.
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"I am focused on making sure we compensate customers as quickly as possible; and on fixing the issues that caused the failure."

ANZ has overhauled its leadership structure in Australia following last year's departure of retail chief Fred Ohlsson, giving two executives joint responsibility for the bank's local financial performance.

Mark Hand has been named Mr Ohlsson's permanent successor as retail chief, and digital banking boss Maile Carnegie is taking on an expanded role as digital and Australia transformation executive.

The pair will jointly share responsibility for ANZ's financial performance in Australia, which chief executive Shayne Elliott indicated was a response to the challenges posed by the financial services royal commission.

"It was clear that retaining a single governance and accountability structure is no longer suitable given the size and complexity of the challenges facing domestic banking in Australia," Mr Elliot said in a statement. 

Mr Ohlsson, who was ANZ's NZ boss before becoming Australia group executive in 2016, stepped down on December 29.

He assisted Mr Hand throughout January. 

Ms Carnegie joined ANZ in 2016 after working for Google as managing director in Australia and New Zealand following 20 years with Proctor and Gamble. 
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The structural changes to the executive management team will come into effect from March this year.