Another season of record profits by New Zealand's foreign-owned banks has prompted the Greens to again call on the government to strengthen Kiwibank.

Westpac's New Zealand operations made a $NZ770 million ($A679.76 million) profit for the year to September, up nine per cent on last year, the bank said on Monday.

Greens co-leader Russel Norman says Westpac, ASB, ANZ and BNZ - all Australian-owned - made a total $NZ3.7 billion ($A3.27 billion) in cash profits, an increase of more than 10 per cent.

"While it's good to have strong banks, the excessive profits of the big four foreign-owned banks are damaging the rest of the New Zealand economy and contributing to our number one problem - a high and persistent current account deficit," he said.

"Record profitability comes at the cost of New Zealand businesses and households that are paying higher than reasonable borrowing costs and bank fees."

Dr Norman said year-on-year record bank profits shouldn't be the norm.

He said New Zealand-owned banks make up only six per cent of the sector, and that had to change.

"We can increase competition in our banking sector by strengthening Kiwibank and other New Zealand-owned banks," he said.

"The challenge for the government is to build them... By injecting capital into Kiwibank and allowing it, in time, to become the government's banker we can increase its capacity to compete fairly with the much bigger Australian banks."

Westpac holds the government's account and the Greens have been complaining about that for years.

 

Advertisement