The Taoiseach, Mr Ahern, has expressed frustration at the decision of the Mahon tribunal to postpone his appearance before the tribunal until after the Easter holiday.
"He wants to get in there and give his side. Nobody has made any allegations against him, but it has been around for years. He wants to get in and to move on," one source close to him told The Irish Times.
The delays could cause "serious problems" if his appearance is delayed until May or June, a government spokeswoman said, because of the pressure of EU and international commitments.
Mr Ahern had been expected to give evidence to the tribunal this week, following the appearance yesterday in Dublin Castle of former cabinet minister Senator Mary O'Rourke.
In her evidence she said she was sure Mr Ahern and other ministers of the time met property developer Mr Tom Gilmartin in Leinster House in 1989. Mr Ahern is among a number of those said to have been present who says he cannot remember the meeting, and he has provided an alibi for one of the suggested dates.
The Taoiseach, who spent some of last weekend preparing to give his testimony to Judge Alan Mahon, has been "on standby" since the beginning of the year, as have two dozen other people.
"He is extremely disappointed that he will not have an opportunity before the Easter break. It does have implications because the tribunal has said that he will not appear before April 21st," the spokeswoman said.
"It is totally non-specific about when he might appear. If it drifts on into May, or even June, it will make things extremely difficult because of his international commitments.
"His diary is completely choc-a-bloc from May with the European Union. Obviously, the local elections will be there as well. That has to be borne in mind," the spokeswoman said.
The worst scenario for Mr Ahern, sources said last night, is that the tribunal would order him to appear on a date that is already booked for international business that could not be rescheduled.
In her evidence Ms O'Rourke, who was minister for education at the time, told the tribunal she was "very sure" she met Mr Gilmartin, "albeit in a perfunctory way", in the presence of other ministers at the 1989 meeting. She was also certain that then fellow minister Mr Pádraig Flynn introduced her to the developer and that the meeting took place in a room opposite her ministerial office in Leinster House.
But she added that she saw nothing "untoward" in the meeting between ministers and a man who was promising to bring thousands of jobs to Ireland at a time when the country was depressed economically. "I thought it was a normal thing and I still do." Even though she says she was present for only 10 seconds, Ms O'Rourke is the only member of the 1989 cabinet to support Mr Gilmartin's claim that a meeting took place.