Gerry Adams has demanded a referendum "to allow Stephen Fry or anyone else" to air their views on God without fear of criminal charges.
A complaint to police about the British comedian's remarks on Irish television that God was stupid, selfish and "quite clearly a maniac" sparked controversy about blasphemy laws.
Under the Defamation Act, blasphemy is punishable by a fine of 25,000 euro in an offence rooted in the Irish constitution.
Sinn Fein leader Mr Adams said a single complaint had led to the "spectacle of Mr Fry being investigated by the gardai on a criminal charge of blasphemy".
"This story was widely reported in the international media with appropriate mocking commentary and some disbelief," he said.
"Blasphemy should have no place in the constitution."
Mr Adams urged Taoiseach Enda Kenny to arrange a referendum - which is needed to change the constitution - as soon as possible to remove the blasphemy clause.
Referencing a famous remark from surreal sitcom Father Ted, he asked: "Will you give citizens the opportunity to say clearly, 'down with that sort of thing', and allow Stephen Fry or anyone else to express an opinion without threat of criminal proceedings?"
Across the chamber, Mr Kenny said the last known prosecution for blasphemy in Ireland was thought to have been in 1855.
There have been no such prosecutions under the Defamation Act, introduced in 2009, he added.
Mr Kenny said it had already been agreed by Government to hold a referendum on the issue, and it was simply a case of "finding an opportunity to deal with this".
Gardai reportedly dropped their investigation because there were no injured parties.
The row erupted after a member of the public contacted police about Fry's interview on RTE's show The Meaning Of Life in February 2015.
The footage went viral after it was aired and has now been seen more than seven million times on YouTube.
Asked what he would say if he was confronted by God, Fry replied: "How dare you create a world in which there is such misery that is not our fault? It's not right. It's utterly, utterly evil.
"Why should I respect a capricious, mean-minded, stupid God who creates a world which is so full of injustice and pain?"
Questioned on how he would react if he was locked outside the pearly gates, he responded: "I would say, 'Bone cancer in children? What's that about?'
"Because the God who created this universe, if it was created by God, is quite clearly a maniac, utter maniac.
"Totally selfish. We have to spend our life on our knees thanking him? What kind of God would do that?"