Australia's largest consumer class action, the 'unfair bank fees' case being run against ANZ Banking Group by Maurice Blackburn Lawyers, will enter its final stage from about 10am today in the High Court in Canberra. The case, which has been on foot since 2010, has been through a Federal Court trial and appeal process - with most grounds of the appeal decided in favour of ANZ. The core point left to be determined is whether late payment fees are an unfair penalty or a reasonable charge for the bank to make.The law firm said it expects the hearing to take up to two days, and then the parties will wait for about two months for the final determination. If the plaintiff lawyers are successful, the case will benefit hundreds of thousands of Australian retail bank customers who have incurred late payment fees on credit cards.Andrew Watson, national head of class actions at Maurice Blackburn, said via media statement ahead of the first day's High Court hearing today: "There has always been a strong public interest in rigorously testing the fees, and it is fitting that the highest court in the land will ultimately resolve Australia's biggest consumer class action." The case is supported by litigation funder IMF Bentham. Other class actions have been started against most banks in Australia, but all have been put on hold pending the outcome of the ANZ case. Similar class actions, shadowing the Australian law firms' arguments over fees and charges, are being run against the major banks in New Zealand. As consumer protection laws are slightly different in each jurisdiction, outcomes may differ on either side of the Tasman.