The State is facing a bill of about €1.35bn for dealing with the victims of child abuse in institutional care, the Oireachtas Public Accounts Committee has been told.
That compares with the €128m that has been contributed by the religious orders.
An original estimate had claimed that it would cost the religious orders about €254m to take all cases to the courts rather than to the Redress Board.
The Comptroller and Auditor General, John Purcell, said it had also emerged that the estimate had in fact been prepared by an official in the Department of Education and not by the religious orders.
He said the average payment so far to each claimant was €76,000, with legal and other costs adding about 20% to that figure.
The One in Four group has said today's revelation shows once again that the church has been 'let away with it.'
One in Four's Advocacy Coordinator, Deirdre Fitzpatrick, said the redress deal was the State's one opportunity to hold the church to account. The State should now explain how the deal was brokered, she said.
Similar sentiments were echoed by Labour Education spokesperson, Jan O'Sullivan, who said the Government had clearly entered into the agreement without properly forecasting the cost.
However, the former Minister for Education, Michael Woods, who brokered the deal in 2001, said the redress scheme had been set up in accordance with the Government and Dáil's wishes.
Mr Woods said it was designed to be open-ended so that it could provide suitable redress for people who had been injured. He added that it was now a matter for the current Minister for Education, Mary Hanafin.
