ANZ New Zealand chief executive David Hisco is stepping down after concerns were raised about his use of corporate chauffeured cars, amid an internal review of his personal expenses.
His health is also a factor in decision.
Mr Hisco did not accept all of the concerns raised by the bank's board, ANZ said in a statement, but accepted he needs to be accountable given his leadership position.
ANZ New Zealand board chair Sir John Key said the board was concerned about how Mr Hisco was "characterising certain expenses and transactions following an internal review of personal expenses".
Sir John said it specifically referred to long-term personal use of corporate chauffeur cars and charging the company for storage, in what he claimed was without proper disclosure.
"The amount in dispute are in the tens of thousands of dollars, we are disappointed David is leaving ANZ under such circumstances.
"It's not about the money itself, it's about the way it was recognised in the ANZ records."
"David will, like anyone else, receive his contractual and statutory entitlements, this equates to 12 months notice and the leave he had accrued," Sir John said.
Mr Hisco had also forfeited his rights to about $6.4m in equity, he said.
His annual pay was more than $3m.
Sir John said Mr Hisco was “adamant that he had authority for the expenditure that was undertaken”.
Antonia Watson, the now-acting chief executive of ANZ New Zealand, said it was a day of "shock and disappointment".
She said Mr Hisco was well liked and had grown ANZ to be a market leader, "but the NZ leadership team and I stand firmly behind Sir John and the ANZ NZ board, in believing David has not met the standards and expectations of the organisation".
It comes after ANZ Bank was censured by the Reserve Bank in May for failing to have enough money on hand to cover risks or losses – and for failing to disclose that for more than four years.
The failure meant ANZ has to hold an extra $277 million dollars of Operational Risk Capital because it has lost the right to work out it’s own capital levels using internal credit models. It must now opt for a more conservative standard model.
Mr Hisco, who is from Australia, had been in charge of New Zealand's largest bank since 2010.