AMP admits it underestimated the scale of its fees-for-no-service problems.
Australia's largest wealth manager is accelerating its remediation program, fearing its past approach would have meant some customers had to wait 17 years to get refunds.
AMP acting CEO Mike Wilkins said the group did not fully appreciate the size and complexity of the issue in 2016.
"I think that AMP believed, as did the industry, that this was not such a large issue," he told the banking royal commission on Tuesday.
Mr Wilkins said the AMP board became concerned late last year and during this year that the remediation process was proceeding too slowly.
AMP now plans to wrap up its remediation within three years.
It has estimated it will cost $778 million to complete the remediation program for clients given inappropriate advice or charged fees for no service.
The amount being paid to customers totals $440 million, the majority being for fees for no service.
The fees-for-no-service scandal revealed at the royal commission in April led to the departure of AMP's CEO and chair, as the inquiry's barristers suggested AMP face criminal charges for lying to the corporate regulator.
Australian Associated Press