The Taoiseach, Mr Ahern, has described the payment of £50,000 by builder Mr Tom Gilmartin to former minister Mr Pádraig Flynn as "extraordinary".
In response to a Dáil question from the Green Party leader, Mr Trevor Sergeant, he conceded that it was not credible that such a payment "would not have strings attached".
"If Mr Gilmartin had told me back in 1989 that he was giving a donation to Mr Flynn, I would assume that he was giving that to Fianna Fáil," Mr Ahern said. "I don't expect any individual expected it wouldn't be without strings attached.
"To get £50,000 in 1989 made out to cash is extraordinary, there's no doubt about that," he said. "There's no hiding that fact that it was a huge contribution not going to the party.
"Obviously, the question arises, what was it for? But that is a matter for the tribunal to resolve."
Labour's Mr Pat Rabbitte asked the Taoiseach if he asked Mr Gilmartin did he ever make a contribution to Fianna Fáil.
Mr Ahern said Mr Gilmartin rang him at least once, but he had no recollection of any conversation.
"I can't recall Mr Gilmartin telling me that he gave £50,000 to Fianna Fáil or that he gave anything to Mr Flynn," he said. "I would never ask anyone would he give money to me or to Fianna Fáil.
"I could well have engaged in conversation with him, but I have no recollection."
