"The bank does not charge customers these fees when there are insufficient funds in an account to meet a direct debit payment or cheque."
BNZ estimated the change had saved its customers around $25 million per annum over the past five years.
Symons said last year the bank had also changed its stance for customers going into unarranged overdraft and only charged a fee if the account was more than $20 overdrawn.
"This has made a big difference for customers who may have accidentally overdrawn their accounts by only a few dollars."
Symons said all its fees were fully disclosed and those being singled out in the case were all avoidable.
Around 5000 BNZ customers have already registered to take part in the court case which can target fees going back six years.
Watch: Fair Play on Fees lawyer Andrew Hooker explains the latest legal action taken against ASB, Westpac and BNZ
Meanwhile Westpac and ASB have both said they intend to vigorously defend any action that is brought.
"We will review the proceedings if and when they are filed and it is our intention to vigorously defend any action that is brought. We continue to encourage customers with concerns to contact us directly," said a Westpac spokesman.
An ASB spokesman said it had seen the announcement made by Hooker.
"We have seen the announcement but we have not yet had any contact from the litigation funders."
ASB said it needed to review the proceedings in detail but intended to vigorously defend the claim.
"We continue to encourage any customers concerned about fees to talk to us directly."
Customers of Westpac, BNZ and ASB who want to join the action have until 11pm February 27 to register online to confirm their inclusion in the case.
Hooker said he would lodge documents against the three banks on February 28.
Last week the Australian Federal Court ruled that ANZ in Australia had been illegally imposing penalties for late payments on credit cards in Australia.
But the court found in favour of the ANZ in the other fees.
New Zealanders can join the action against unfair bank fees by registering at: www.fairplayonfees.co.nz.