"The judge has ruled the maximum it is okay to charge is A$3. That obviously endorses the position we have taken that charging $15 for late credit card payments is wrong."
Hooker who last year filed cases against the ANZ and Kiwibank said it was also encouraged by the judge ruling that the limitation period for claims may be extended beyond six years.
"Up until 2009 banks were charging much higher fees in New Zealand."
In terms of the other charges being dismissed Hooker said he was still trying to digest that and what it meant in terms of New Zealand law.
He said the ruling may only be round one in the Australian case.
"I'm sure that both sides will appeal."
The ruling would not alter the cases against the banks here in New Zealand, he said.
"It's onwards and upwards in our cases."
He expected to file against the three remaining major banks - ASB, BNZ and Westpac by the end of February or early March at the latest.
The Australian ruling has wider implications, with the ANZ case only the first of eight planned class actions involving 185,300 customers of eight lenders, claiming $243 million in damages.
Law firm Maurice Blackburn, which is representing the bank's customers, has previously suggested that if it wins it could then involve potentially millions of bank customers hit by billions of dollars in fees.
Justice Gordon's ruling effectively means ANZ was not entitled to charge an extra cost of between $20 and $45 if a customer did not pay their minimum credit card bill on time, because it represented an illegal penalty and did not reflect its true cost.
ANZ had admitted that it had breached its contract by charging those "exception" fees, Justice Gordon said.
An ANZ New Zealand spokesman said the bank was pleased that today's decision by the Australian Federal Court found in favour of ANZ Australia on four of the five exception fees.
"In relation to credit card late payment fees, we're still considering the judgment and its relevance to New Zealand. In the New Zealand context, the Commerce Commission determined in 2010 that ANZ Bank New Zealand's credit card late payment fees were not unreasonable."
ANZ re-iterated that it would be defending the New Zealand claim "vigorously".
- AAP with NZ Herald