The final bill for the legal and administrative costs of the Residential Institutions Redress Board could rise to well over €200 million, or one fifth of its total costs by the time the board has completed its work, according to Government estimates.
The figures, released by Minister for Education Mary Hanafin, also show that it has paid out approximately €714 million to date, including €91 million in legal costs alone.
Answering a Dáil question on the topic last week, Ms Hanafin told Labour Party TD Seán Sherlock that the board, which provides compensation to victims of abuse in orphanages and industrial schools, may need an additional €428 million.
This would bring the total costs of the board to €1.14 billion, although this could rise to as much as €1.3 billion, she said.
Five years ago 18 religious orders paid over €128 million in cash and property to the State as part of a deal whereby they were granted indemnity against future legal actions by former residents.
The congregations had managed the orphanages and schools in which the abuse had taken place.
The Department of Education originally estimated that the compensation scheme would cost about €250 million, but later revised this figure to over €600 million. However, in 2003, the Comptroller and Auditor General projected that the scheme could cost up to €1 billion.
More than 9,200 cases have been completed out of a total of over 14,500 applications received.
The average award currently stands at €67,755, with the highest award being €300,000.
"Based on the total number of applications received, the final cost of the scheme may be somewhere between €1 billion and €1.3 billion, including legal and admin costs which are running at approximately 20 per cent of awards," Ms Hanafin said.
"I should emphasise, however, that this revised estimate, like earlier estimates, is tentative as the board has some 5,270 outstanding applications to process and the level of award in these remaining cases may vary substantially.
"The final cost of the scheme will not be known until the board has completed its work, which may take up to a further three years."
Some people have bypassed the board and gone directly to the courts.