In November 2013 Kiwibank was named as a target by lawyer Andrew Hooker in its campaign for fair fees.
Hooker is taking on all the major banks in a class-action style suit aimed at clawing back money for customers on past transactions where he believes they have been charged excessive fees.
The case is targeting fees which include late payment and over limit credit card fees, fees charged when cheques bounce and when accounts go into an unarranged overdraft.
Similar action in Australia against ANZ bank initially ruled in favour of the customers for late payment credit card fees but it was overturned in April by the Australian Federal Court.
Lawyers for that action have said they will try and take an appeal to the High Court.
The action is New Zealand has been on hold awaiting the outcome of the Australian case.
Hooker said he was not aware of anything he had done to prompt the Kiwibank move but it was good news from his perspective.
"We are pleased to see Kiwibank reducing its fees."
A spokesman for Kiwibank said the rate changes were not connected to the legal action.
"We assess our rates and fees all the time and make changes where we believe it is appropriate to do so."
The spokesman said there were pending changes to credit laws and the bank believed now was the right time to make the fee changes.
Changes to New Zealand's consumer credit laws came into force on June 6 and include requirements for lenders to be more responsible about giving out money, give a warning on credit card statements about paying the minimum balance, publicly displaying interest rates and fees and ensuring customers are notified about fee changes which could cost them more money.
Read more about the consumer credit law changes here.
As well as the fee cuts Kiwibank is lifting its interest rates from July 6 from 19.95 per cent per annum to 20.95 per cent per annum for purchases and from 21.95 per cent per annum to 22.95 per cent per annum on cash advances for it Air New Zealand Airpoints Platinum mastercard.
The Kiwibank spokesman said it regularly compared its fees to rival banks and was also making the changes to remain competitive.
He said there had a been a "muted reaction" from customers who had received the letters telling them of the changes as most people did not incur those fees.