Reserve Bank governor Graeme Wheeler has rejected claims by the Greens that he is biased in favour of the banks he has to regulate.
Greens co-leader Russel Norman has accused Wheeler of misleading Parliament, when he told the finance and expenditure select committee last month that when New Zealand banks' return on assets were compared with most OECD countries, "we are in fact about average or below".
The OECD includes European countries, many of whose banks are under some strain.
Among 16 advanced economies outside the euro area, New Zealand's banks rank fifth, between Australia and Canada, for return on assets, when returns are calculated before tax and extraordinaries, according to data which was still being compiled by the Reserve Bank when Wheeler appeared before the select committee.
"Our new governor's complacency about bank profitability is concerning," Norman said. "His job is to regulate our banks, not be their champion."