A former Supreme Court judge has criticised the Flood tribunal interim report as without "legal standing".
Mr Hugh O'Flaherty, who resigned from the Supreme Court over his involvement in the Sheedy drink driving case, criticised "one-person tribunals" as a "very bad precedent".
The Flood inquiry has now become a three-person tribunal.
Mr O'Flaherty said the Flood tribunal was "legally sterile" and that findings of guilt could only be made at trials.
He said the "fact that there are very serious findings made against individuals is of great consequence to them and to their families. That's why findings of guilt on serious criminal charges can only be made at trials with judge and jury - not tribunals."
The one-person tribunal was a bad precedent, because "it needs at least three people to consider evidence. I don't believe a judge can decide by the demeanour of a witness whether he is telling the truth or not. Also, when there are three persons, decisions can be made as the inquiry progresses - and that speeds things up."
Mr O'Flaherty was commenting in The Dubliner magazine, in a regular column he writes, called "The Prosecution".
He questioned whether tribunals were the right type of inquiry and criticised their duration. The legislation which established tribunals "never contemplated inquiries that would drag on for five years".
The former member of the State's highest court also criticised the handling of the inquiry into the shooting dead of John Carthy by gardaí in Abbeylara.
It went from a Dáil sub-committee investigation to the High Court and then the Supreme Court, where the Dáil learned it had "no power to carry out such an investigation".
He said "millions of euros are wasted on a futile exercise".
The correct procedure would have been to appoint a tribunal of three judges, to report within six months.
Mr O'Flaherty also criticised the Minister for Justice, Mr McDowell, over his plan to set up an expert group to report on defamation laws.
The former judge said there were umpteen reports "gathering dust" and the "bottom line" was that "politicians and journalists are happy to keep the libel laws in their antiquated state.
"They avail of the courts to vindicate their good names more than anyone else."