A Minister of State has described John McGuinness as an "absolutely brilliant" chairperson of the Oireachtas Public Accounts Committee when he served in the role.

Minister Patrick O'Donovan said that Mr McGuinness made sure that the committee stuck to its task of examining public expenditure as set out by the Comptroller and Auditor General.

The Minister said he was not referring to today's Supreme Court judgment, which found that the PAC had acted outside its terms of reference in its dealings with the former chief executive of Rehab Angela Kerins.

Mr O'Donovan said too that the Oireachtas needs to set out boundaries about what committees should be doing.

He asked was it appropriate that five and six committees are sometimes vying to get witnesses to appear before them during the "latest controversy."

"There should be very clear boundaries and if necessary we need to come together to set out those boundaries," he said.