The Taoiseach Enda Kenny says Gerry Adams knows who Paudie McGahon's alleged rapist is.
He also said that Sinn Féin needs to "get its act together" to report sexual abuse.
Mr Kenny says the Sinn Féín president needs to tell Gardaí immediately about all aspects of IRA abuse, including why it is necessary to have designated 'safe houses' for kangaroo courts.
Speaking in Atlanta on his St Patrick's Day tour, the Taoiseach insists Gerry Adams would be fully aware of all the details of Paudie McGahon's case, and others.
He said: "The Sinn Féin Party should get its act together. This is about the abuse of children, about the rape of children, about paedophiles being moved deliberately out of one area into another.
"Gerry Adams himself believes that Mr McGahon was raped and abused, he knows who did it.
"The consequences of that are clear, you bring the information the gardaí, and bring it immediately."
Gerry Adams has dismissed the remarks by Taoiseach Enda Kenny in the United States as "opportunistic and demeaning to his office".
Deputy Adams said: "Mr Kenny says that I should go to the Gardaí about anything that I know regarding issues of sexual abuse. He says this in the full knowledge that I have already done this.
"The Taoiseach's refusal to act on Martin McGuinness's proposal for an all-Ireland mechanism to assist survivors and victims of abuse and his failure even to write to deputy First Minister for over four months, speaks loudly of his attitude to this serious and sensitive issue.”
"The Government has yet to put together an all-Ireland sex offenders register and they have cut funding to rape crisis centres and advocacy group.”
"Mr Kenny is more interested in exploiting it to attack me and Sinn Féin. His remarks are both opportunistic and demeaning to his office."