Law firm Maurice Blackburn Lawyers on May 30 filed a class action against AMP Ltd. for allegedly charging its superannuation members unreasonable fees.

The law firm said in a statement that material tendered during hearings of the Royal Commission into Misconduct in the Banking, Superannuation and Financial Services Industry revealed that AMP's superannuation funds were charging uncompetitive administration fees, with high costs exceeding returns and causing investment losses in some instances. The class action builds on the commission's findings and claims that the AMP trustees failed to monitor, compare, negotiate or seek reductions of hefty fees being pocketed by related AMP group companies.

The class action is being supported by litigation funder Harbour.

Maurice Blackburn is seeking a refund plus the extra returns the members missed out on, The Australian Financial Review reported, citing the firm's principal lawyer, Brooke Dellavedova. About 1 million super members were affected by the high fees, Dellavedova said, noting that total compensation could be "hundreds of millions of dollars."

This is the second class action Maurice Blackburn filed against AMP. The firm, along with rival firm Slater & Gordon, filed a class action over AMP's involvement in the fee-for-no-service scandal. AMP admitted to charging customers for financial advice they did not receive and lying to the corporate regulator about its behavior.

Responding to the latest class action, AMP said in a statement that the "proceeding will be vigorously defended."