The "big four" Australian-owned banks will not make submissions to a parliamentary committee set-up by opposition MPs to investigate their behaviour.
Labour, the Greens and the Progressive Party are holding the inquiry into the difference between bank interest rates and the official cash rate set by the Reserve Bank.
They decided to hold it after government MPs used their majority on the finance and expenditure select committee to block an inquiry.
Labour finance spokesman David Cunliffe said he received letters from ANZ-National, Westpac, ASB and BNZ ahead of yesterday's submissions deadline.
All four declined to appear before the committee.
"If they had a good story and good data they should put it before the inquiry so we can make a fact-based judgment," Mr Cunliffe told the New Zealand Herald.
The inquiry was still useful, he said.
Kiwibank chief executive Sam Knowles will appear.
About 40 submissions had been received from banking customers, interest groups and lobby groups.
The committee sits Wednesday and Thursday at Parliament and is open to the public.
