New Zealand's banks set a sector profit record in 2017, their profits rising 7.35 per cent to $5.1 billion.
It was complete reversal of the previous year's $3.17m drop in profits, KPMG's Financial Institutions Performance Survey says.
The increase was largely attributed to improvements in the dairy industry and national economy.
"In contrast to 2016, the banking sector produced an impressive increase in profitability. The combination of growth in net interest income and non-interest income, as well as a significant increase in asset quality, has contributed to this record result," KPMG audit partner John Kensington said.
Banks' total assets continued to grow in 2017, reaching a new high of $504b, with all five major banks reporting increases in their loan books of between 1 per cent and 7.57 per cent.
However, major bank growth slowed compared to last year and they appeared less competitive in the lending market, KPMG said.