Australia and New Zealand Banking Group said on Wednesday it will vigorously defend a class action suit by customers for recovery of bank fees.

Earlier class-action law firm Maurice Blackburn said it would file a $48 million class action suit against ANZ, with up to 11 other lenders at risk of similar suits in the future.

The suit is against exception fees, which include charges for insufficient funds, overdrawn bank or credit card accounts and late credit card payments.

"We recognised that these fees were unpopular with customers. This is why we took action to simplify fees," the CEO for its Australian operations Philip Chronican said in a statement.