Former Government minister Michael Lowry has denounced the Moriarty Tribunal as an out-of-control legal farce after it called new witnesses.
The independent TD at the centre of the long-running investigation has also demanded that barristers who had overcharged the State for their work on the tribunal be pursued.
Mr Lowry hit out after two officials from the Attorney General's office were called to testify at the tribunal about the awarding of a mobile phone licence to tycoon Denis O'Brien in 1996, when the TD was Communications Minister.
"I have a lot of experience -- 13 years -- dealing with this tribunal, and I have come to the opinion this quasi-judicial legal farce is out of control for years," he said.
Demanding an explanation from Taoiseach Brian Cowen about the costs, he said the Oireachtas has stood back and allowed senior tribunal barristers get paid €2,250 every day, including weekends, at a time when social welfare, public pay and health service spending was being cut.
Mr Cowen said the new commissions of investigation would allow matters of urgent public importance be dealt with quicker and cheaper in future.
The tribunal has cost the Taoiseach's Department €38.27m since 1997, and other government departments have been hit with an estimated €10m bill to date from the inquiry.
The final cost is expected to be several times this figure when third-party costs are paid.