The Taoiseach, Mr Ahern, has told the Mahon tribunal that he has no recollection of meeting Mr Tom Gilmartin in February 1989 but conceded "an informal meeting" with the property developer may have taken place.
Mr Gilmartin claims Mr Ahern was among a group of Fianna Fáil ministers he met in Leinster House at the time.
However Mr Ahern has consistently claimed that he has no memory of meeting Mr Gilmartin in the company of other ministers and that he had a "firm belief" he did not attend such a meeting.
But in his evidence to the tribunal today, Mr Ahern said while he did not believe any meeting in "a formal sense" took place, an "informal gathering" could well have occurred.
Mr Ahern said it was, and still is, a "regular occurrence for a minister to pull a few colleagues aside to meet certain people". He maintained "casual chit-chats between ministers" and certain individuals happened all the time in Leinster House.
But as far as he was concerned there was no such meeting between Fianna Fáil ministers and Mr Gilmartin in any "formal sense", or else it would have been recorded in ministers' diaries.
However, under questioning from Mr John Gallagher SC, for the tribunal, Mr Ahern conceded "a casual encounter" could have taken place.
The leader of the Senate, Mrs Mary O'Rourke, who was the minister of education at the time, is the only member of the 1989 cabinet to support Mr Gilmartin's claim that a meeting took place.
The other ministers alleged to have been present, including the former taoiseach Mr Charles Haughey, Mr Seamus Brennan, Mr Padraig Flynn, Mr Ray McSharry and Mr Ray Burke either cannot recollect the meeting or say it did not take place.
Mr Gilmartin claims he was subjected to a £5 million extortion demand immediately after leaving the meeting.
On Monday, Mrs O'Rourke backed-up Mr Gilmartin's claim, saying she had briefly attended a "gathering" of ministers in the Dail at which she was introduced to Mr Gilmartin.
