Almost 39,000 people have now signed up to take part in legal action against alleged unfair penalty fees charged by New Zealand banks.
And that number is expected to top 50,000 as announcements against more banks are made in coming months. So Far ANZ and Kiwibank have been targeted.
The Fair Play on Fees campaign claims default fees charged by banks in situations such as unarranged overdrafts, bounced cheques and late and over-limit credit card fees are "unenforceable penalties" and should be paid back to customers.
Auckland lawyer Andrew Hooker, who is leading the campaign, said the response from New Zealand bank customers had been outstanding.
"The case against ANZ resulted in more than 17,000 customers signing up to our campaign. A similar legal action taken against ANZ customers in Australia attracted about 38,000 customers," Hooker said.
Kiwibank, ASB, BNZ and Westpac customers could still sign up, he said.
In its statement of defence the ANZ said that when customers opened an account with it they agreed to certain terms and conditions including what fees would be incurred for specific "events" such as late payment and unarranged overdrafts.
The New Zealand legal action is being run on a "no win no fee" basis, which means no upfront costs. People can join the lawsuit by registering at: www.fairplayonfees.co.nz