Lawyers for the Taoiseach, Mr Ahern were told to ask him directly about an alleged meeting which property developer Mr Tom Gilmartin says took place in Leinster House in 1989.
During cross examination at the Mahon tribunal by Mr Conor Maguire SC, for Mr Ahern, Mr Gilmartin said he attended a meeting with Mr Ahern in or around February 1st at Leinster House along with the then Taoiseach, Mr Charles Haughey, former ministers Mr Padraig Flynn and Ray Burke and Minister for Transport, Mr Brennan and others including former Taoiseach, Mr Albert Reynolds.
Mr Gilmartin was trying to develop lands in Bachelors Walk and Quarryvale into shopping centres and claims to have been brought to the meeting by Mr Liam Lawlor.
"We [Mr Gilmartin and Mr Ahern] were on a first name basis. I had met with him twice already. Anyone who says they were not at the meeting is lying," Mr Gilmartin said.
It had been put to the property developer that the meeting could not have taken place when he said it did because, according to Mr Gilmartin's evidence, Mr Haughey had told him his son, Sean, would become Lord Mayor of Dublin and that this did not happen till July 3rd, 1989.
"Maybe he [Mr Charles Haughey] was clairvoyant," replied Mr Gilmartin.
"If you're trying to find some sort of mix up [in Mr Gilmartin's evidence] so Mr Ahern can cover his ass, you can forget about it," He told Mr Maguire.
"Why is it that the Government of the country, or most of it, is lying about a meeting where there was only chit chat and nothing turned on it," Mr Gilmartin asked.
He also put to Mr Maguire that perhaps the Taoiseach had doctored his diary on the events of February 1989 and the alleged meeting in Leinster House.
Mr Maguire had been probing various inconsistencies between the written and verbal evidence given by Mr Gilmartin and asked the witness if his evidence was just a "general flavour" of events or was it a verbatim account.
The Co Sligo-born businessman answered that he accepted there were inaccuracies in his written statement and that he had corrected these in verbal evidence to the tribunal.
He also said he never told Inspector Hugh Srennan that Mr Liam Lawlor demanded €5 million from him in 1988 to help "smooth" the process of developing shopping centres at Bachelors Walk and Quarryvale. Inspector Srennan interviewed Mr Gilmartin in 1989 in connection with corruption allegations made by the property developer.
Earlier, while finishing his direct evidence to the tribunal, Mr Gilmartin said that his wife and he were sorry for the position former Fianna Fáil minister, Mr Pádraig Flynn, ended up in as a result of his dealings with him.
Describing a series of phone calls between the two men in 1998, Mr Gilmartin said he told Mr Flynn: "I feel very bad you wound up in this position because you are not the worst of them".
Mr Gilmartin claimed yesterday Mr Flynn telephoned him to ask him to lie to the tribunal by pretending that the politician had returned a £50,000 donation from him.
Mr Gilmartin has yet to face cross-examination for lawyers for Mr Flynn and several other Fianna Fáil politicians against whom he has made allegations.
Former TD Mr Liam Lawlor and jailed former assistant Dublin city and county manager George Redmond are also expected to question Mr Gilmartin over his claims they hounded him for money. Neither of the two men has legal representation. Mr Lawlor claims he cannot afford any more lawyers and Redmond is serving a 12-month term in Cloverhill prison for corruption.
Before the start of this morning's session, the public were asked to refrain from responding with laughter and cheers to Mr Gilmartin's evidence. Tribunal staff placed leaflets on the seats in the public gallery asking members "to refrain from laughing, clapping and otherwise making unnecessary noise while evidence is being given".
Yesterday, Judge Alan Mahon had to interrupt proceedings to call for quiet twice when Mr Gilmartin prompted applause from the several hundred people present when he decried politicians of the late 1980s for being more concerned with "feathering their nests" than the plight of impoverished Irish people.
"I came into a country that was on its knees, with queues outside the American embassy and kids begging on the London underground," Mr Gilmartin said. "I think it was despicable that people running the country had no interest in anything other than feathering their own nests."