A judge will decide later whether to grant food critic Helen Lucy Burke disclosure of documents she claims will show Senator David Norris had an ambivalent attitude towards underage sex and incest.
Sen Norris, who came fifth out of seven candidates in the 2011 Presidential election, is suing Ms Burke and RTE Commercial Enterprises for libel over views she aired on a Liveline programme some months before the election.
The broadcast, on May 30, 2011, related to a conversation between Norris and Burke over a meal in January 2002 for the purposes of an article she later wrote for Magill magazine.
Sen Norris is also suing over a subsequent Liveline programme, six days before the election, which discussed an eight-minute recording of that 2002 conversation which was also broadcast.
Sen Norris claims his reputation has been damaged by the two broadcasts and that the words used in them meant, among other things, that he held evil beliefs and was unfit to be President or to hold public office.
He says views were falsely attributed to him in the May 2011 broadcast which he never held or expressed. The quoted material was false and a deliberate distortion of what he actually said in his 2002 interview with Ms Burke.
The second broadcast was a deliberate attempt to sabotage his candidacy in the election, he says.
Ms Burke says, in her defence, that her opinions of Sen Norris were based on allegations of fact specified in the programmes and they related to a matter of public interest.
She also says, among other defences, that the words were published in good faith, were honestly held and that it was reasonable and fair to publish them.
She denies Sen Norris was defamed, says he never challenged the Magill article she wrote based on that interview and that she accurately reported both him and the tenor of that 2002 conversation.
In advance of the trial of the defamation action, Ms Burke brought a High Court discovery application against Sen Norris seeking documentation she says she needs in order for her to show his claim is unsustainable.
She says it relates to representations Norris made in 1997 to the Israeli courts, on Seanad Eireann notepaper, urging clemency for the senator's former partner, Ezra Yizhak Nawi, who had been convicted 1992 for statutory rape of a 15-year-old boy.
She also wants any material he has relating to his support for poet Cathal O'Searcaigh who had been subject of a TV documentary, called "Fairytale of Kathmandu" which detailed Mr O'Searcaigh's relationship with Nepalese teenage boys.
Peter Shanley BL, for Ms Burke, said the material is required because his client believes it will support her contention that the senator had an ambivalent attitude towards underage sex between men and boys and to sexual relations generally.
Michael McDowell SC, for Sen Norris, said the claims being made in this application were far fetched and outrageous.
The "malicious" allegations being made here were that Sen Norris was in favour of parents having sex with children and of breaking the law. Seeking material related to the O'Searcaigh documentary, which post-dated the Liveline programmes, was "frankly a disgraceful application to make."
The discovery application was a "fishing expedition", counsel said.
It was also brought in circumstances where it was originally pleaded by Ms Burke that the allegations of favouring underage sex and breaking the law were true, counsel said. This application was now an attempt transmute the case into something else and to "dredge up any material" in order to say, instead of saying it is true, that he has an ambivalent attitude.
High Court president Mr Justice Nicholas Kearns said he would give a decision as soon as possible.