National party leader Christopher Luxon says he would like to see a select committee inquiry into the banking sector.
According to the most recent figures, it's understood the Australian-owned banks make more than $16 million in profit every day.
The Reserve Bank and the Commerce Commission are calling for a market inquiry.
Luxon told Morning Report it's important to look at whether there are barriers to competition in the market.
Luxon said a quick study, rather than a full Commerce Commission inquiry, will get answers more quickly at a time when questions about the cost of living and interest rates are crucial.
