The Taoiseach has said that any decision on awarding legal costs at the Morris Tribunal cannot be made until the current module is finished.
Speaking in the Dáil this morning, Mr Ahern said that under the terms of the Tribunal of Inquiries Act, the question of costs was solely a matter for the tribunal.
Donegal publican Frank McBrearty Snr walked out of the garda corruption inquiry yesterday because his legal team could not be guaranteed costs.
Alleged garda intimidation against Mr McBrearty and his extended family led to the set-up of the tribunal in 2002.
Opposition TDs today called on the Government to provide legal representation to Mr McBrearty, who sat in the Dáil public gallery with his wife and daughter.
The chairman of the tribunal, Justice Frederick Morris had awarded costs at the end of the last module, and exercised his right to reduce or refuse legal costs where he judged witnesses to have been uncooperative or to have told lies.
"If you give a guarantee of costs before a module, then you can't have a situation where the tribunal chairman can make a judgment on who co-operated," Mr Ahern said.
The issue was raised by Fine Gael leader Enda Kenny, Labour leader Pat Rabbitte and Labour TD Joe Costelloe, who tabled a Standing Order motion to call for an urgent debate on the issue.
Mr Rabbitte said that a previous Minister for Justice had made an exception and granted legal aid in the Stardust Tribunal of Inquiry in 1981. "There is a precedent without abrogating the rights of the chairman of the tribunal in this particular case," he added.
The Labour leader asked Mr Ahern if there were any plans to debate the tribunal's first report, published last summer and Mr Ahern said he would look into the matter. "Personally I'd have no difficulty. I don't know if there's any implications for a tribunal if you discuss part of it," Mr Ahern said.