Former Press Ombudsman John Horgan said he is "flabbergasted" that media organisations have to go to the High Court to clarify if they can report on what is said under Dail privilege.
The professor of journalism was speaking as RTE and a number of other media outlets were due before the High Court today to clarify if they can report on comments made by Independent TD Catherine Murphy on businessman Denis O'Brien's financial affairs under Dail privilege.
"One of the things that has always seemed to me to be sacrosanct is the right of the media to report what is being said in parliament without fear or favour, and I cannot think of any reason why that should be interfered with," he said.
He also stressed that TDs should be careful how they use Dail privilege.
"It doesn't mean to say that everything that's said in parliament is correct or truthful, but it is one of the foundation stones of our democracy.
"I'm really surprised that it should have ended up in court," he added.
"I don't think it's appropriate for the courts to be deciding on this particular element of the Constitution in this way.
"The question of how you police the Dail under our Constitution is a matter for the Dail itself.
"Whether that policing action is good, bad or indifferent or whether there should be new structures and new forms of accountability built to control what is said is a matter for the Dail itself and not a matter for the courts," he explained.
"It's a sad day really when, as it appears, this issue of the freedom of the press is going to be decided effectively in the High Court, perhaps also in the Supreme Court," he said.
Meanwhile, Health Minister Leo Varadkar has said politicians should be free from the threat of legal action when speaking in the chamber.
However, Mr Varadkar also warned that politicians should be "careful" not to abuse the privilege by revealing personal information that might be false.
"I would agree that Dail privilege is unrestricted and should be. The Constitution is clear on that, but politicians need to be careful not to abuse it," Mr Varadkar told the Herald.
Tanaiste Joan Burton also broke her silence to insist Dail privilege - and the media's right to report on it - was a "cornerstone of our democracy".
"The Tanaiste believes that constitutional protection for TDs and senators to speak freely in the Dail and Seanad on matters of concern - and for the media to report it - is an absolute cornerstone of our democracy," the Tanaiste's spokesperson said.
RTE has lodged paperwork with the High Court seeking to clarify if it can broadcast last Wednesday's Dail speech made by Independent TD Catherine Murphy detailing businessman Denis O'Brien's banking arrangements with Irish Bank Resolution Corporation (IBRC).
Fianna Fail have also called on the Houses of the Oireachtas to join the High Court case being taken by RTE, the Irish Times and the Sunday Business Post.