Taoiseach Enda Kenny has said he doesn't believe the denials of Sinn Féin president Gerry Adams that he wasn't aware of the IRA sex abuses cases or that "kangaroo courts" were held to investigate them.

Speaking on his St Patrick's Day visit to the United States, Mr Kenny challenged Mr Adams to follow his own advice to others and to "present himself" to the Garda and tell them what he knows about the cases of abuse victims Paudie McGahon and Maíria Cahill.

The Taoiseach disputed the assertions by Mr Adams that he was not aware of the identity of Mr McGahon’s alleged abuser or his whereabouts.

“I don’t believe the leader of the Sinn Féin Party when he says he didn’t know about these things,” he said.

Mr McGahon (40), from Co Louth, claims he was raped by an IRA man at the age of 17 in the early 1990s and interrogated by a "kangaroo court" set up by the paramilitary group in 2002. He was asked how his attacker should be punished and the alleged abuser was ultimately sent to England.

Mr Kenny said he was "quite sure" that Mr Adams, a man he said was around Northern Ireland politics for 40 years, "would have been well aware" of what had happened in these cases and that he knows the person alleged to have committed the abuse.

“What are safe houses for? Are safe houses for raping people? Are they for interrogations? Are they for kangaroo courts?” he said.

“Gerry Adams knows full well what they are for. He knows what they are. He knows the people that were involved in them.”

Mr Adams has rejected claims that his party had investigated cases of sexual abuse. He first became aware of Mr McGahon’s claims in 2009, he said, and his alleged abuser was on a list handed to the Garda in November.

The Sinn Féin leader “has a duty now to live up to his own words and go to the gardaí in this case and tell them everything he knows, about paedophiles that may have been moved south, about paedophiles that may have had access to children in the jurisdiction of the Republic, about this safe house, about who organised it,” said Mr Kenny.

Speaking in Atlanta on the first day of his six-day US visit, the Taoiseach hinted that the Government may take some action into the allegations of sexual abuse by IRA members.

“This is something I am not going to stand for and obviously I will consider what action the Government might be able to take,” he said.

He said that responsibility rests on Sinn Féin and Mr Adams to deal with the allegations in the first instance.

“Sinn Féin should get its act together,” said Mr Kenny. “This is about the abuse of children, about the rape of children, about paedophiles being moved deliberately out of one area into another.”

He pointed out that Mr Adams himself believes Mr McGahon was raped and abused.

“He knows who did it,” he said. “The consequence of that are clear - you bring that information to the gardaí, to the authorities and you bring it immediately, not just in this case but in other cases that are known as well.”