Prime Minister Jacinda Ardern has admitted there is work for the Government to after a review of the country's retail banks.

A sector-wide review has found bank staff engaged in poor customer conduct and a lack of willingness to fix mistakes, such as being overcharged interest or fees.

Jacinda Ardern told Mike Hosking the biggest issue for her is that there is not enough monitoring of incentives, with a gap between regulation and enforcement.

"The first priority is to get the banks to fix it themselves, but the reserve bank has also said there is work for the government to do to fill the gap."

LISTEN ABOVE AS JACINDA ARDERN SPEAKS TO MIKE HOSKING