There are suggestions the banking sector is already cleaning itself up.

ANZ New Zealand CEO David Hisco is stepping down after red flags were raised from thousands of dollars of personal expenses on chauffeuring and wine storage.

Massey University bank researcher Claire Matthews told Mike Hosking it was picked up because the Australian CEO ordered a review.

She says it's one thing that's come out of the woodwork, as banks put a microscope over their actions in the past.

"I think it's a result of what happened in Australia, the investigations by the FMA and reserve bank.

"Banks are now looking more closely at what they are doing and what has been going on, which they may not have known about in the past."