The US has given "unqualified and categorical" assurances that it is not transporting prisoners through Shannon, the Taoiseach has said.
Mr Ahern told the Dáil that the Minister for Foreign Affairs had received personal guarantees from the US Secretary of State Condolezza Rice that no US prisoners had been transferred through Irish airports "at any time".
He said the Government condemned the practice of so-called extraordinary renditions and was wholly opposed to torture or any breaches of international law.
The Taoiseach was responding to a question from Labour leader Pat Rabbitte during the first Dail sitting since the Christmas recess.
Mr Rabbitte said there was "acute concern in this country that the US is being facilitated in what they call extraordinary renditions at Shannon."
He said the reliance on diplomatic assurances was not sufficient to protect against the risk of torture and ill treatment of prisoners.
The Labour leader said while the US represented a friendly country it had "duped" the Government in terms of its reasons for going to war in Iraq.
He asked the Taoiseach if he would take steps to reassure the Irish public that the "obnoxious" policy of rendition is not being facilitated at Shannon.
But Mr Ahern said that he has had "unqualified and categorical" from Ms Rice and from the US ambassador as late as yesterday that Irish territory was not being used to ship detainees.
He said to go beyond that could only mean calling senior US officials "one thing" and that he was not prepared to do that.
