Tánaiste Michael McDowell has said there are "very significant matters of concern" arising from the payment of £8,000 sterling to the Taoiseach at an event in September 1994 in Manchester.
Questioned today by reporters Mr McDowell said a statement issued by the Progressive Democrats had not dealt with this issue "because at that time we didn't have the facts and we felt that it would be inappropriate to comment".
However, following a conversation with the Mr Ahern today, Mr McDowell said there were a significant number of issues that needed "to be clarified now".
Mr McDowell said, according to the Taoiseach, "there's a suggestion that a group of businessmen not all of whom were known to him gave £8,000 sterling to him so that he is not now in a position to identify precisely who gave him what and that was a significant sum of money by any standard"
The Tánaiste said it was important to identify the donors in so far as possible and to establish the nature of the event. Mr McDowell said he also wanted to know what the funds were intended for and "what were they used for".
The final matter for clarification was what category the donation fitted into: "was it a gift alone, a political donation, a personal donation?", he asked.
Mr McDowell said he would speak to the Taoiseach again to clarify these matters but could not say when this discussion would take place.
He denied that the future of the Government was rising on this issue but added: "It's important to everyone in Government that there should be accountability and credibility. And that issues which concern the public should be addressed in a way, which maintains and sustains public confidence in the Government."
Mr McDowell said he had not addressed the issue of the payments in Manchester before now because he had to first seek clarification on the issue of the IR£39,000 loans made to Mr Ahern in December 1993 and in 1994.
The Tánaiste added that it appeared that the payment received in Manchester was a gift.
"The Taoiseach has emphasised that this was not an official function that he travelled privately that he didn't have an official script and that he wasn't speaking in his capacity as Minister.
"So I don't think it can be seen as a fee for an official engagement or something like that and I also understand that he does not categorise it as loan so in those circumstances I suppose it would have to be seen as a gift or as a political donation and I understand that he doesn't see it as a political donation and that leaves the category of gift," Mr McDowell said.
He said the tax status of the money was not the primary issue. It's status in terms of standards, that's the crucial thing and whether it can be defended," Mr McDowell said.
Mr Ahern mentioned the Manchester payment during Tuesday evening's television interview.
On the Manchester payment, Mr Ahern said today: "I'm a regular visitor to Manchester, have been for 34 years. I've always been very involved with the Irish community in Manchester.
"I did the dinner a number of times . . . often go along, you know, to speak about what's going on in Ireland, what's happening . . . was it official? No, it was not an offical dinner, I had no official script, my costs in Manchester I paid myself as I always do," he said.
"So, no official script, not an official function, not in my capacity as Minister, paid my own way, spoke at the function and on one occasion the assembled group of about 25, plus the group who were with me from Ireland, gave me the sum of money that I mentioned. That's all that happened."
Mr Ahern went on to say he had "checked the ethics" and "it was found to be in order".
He added: "And I checked the tax position because a sum like that from outside the State up until 1999 wasn't taxable so that was it. Needless to say, it was not something I asked for, it was totally a surprise to me," he said.
However, Labour Party leader Pat Rabbitte dismissed Mr Ahern's explanation and said the Taoiseach now faces the most serious questions of any head of government since Charles Haughey.
"The issue is not whether the receipt of this money was a breach of the Ethics in Public Office Act, that had not come into operation at that stage ... The real issue is that it has been a basic principle and requirement since the foundation of the state that Cabinet members do not accept payments for engagements.
"Cabinet guidelines also state quite clearly that ministers cannot carry on a professional practice while holding office," Mr Rabbitte said.
Fine Gael's Environment Spokesman Fergus O'Dowd said Mr Ahern's statement deepened his problems and introduced more people into the controversy. He queried who Mr Ahern checked the ethical position with, suggesting that then taoiseach Albert Reynolds would likely have been informed under the rules at the time.
Mr Ahern's comments today conflicted with his account of events on Tuesday, Mr O'Dowd added.
"He said on Tuesday that he spoke at a function in Manchester with a business organisation. Today there is no mention of a business organisation. Today we found out that there were people from Ireland present at the meeting. "We need to know who the people at the meeting were and what the purpose of the meeting was," Mr O'Dowd said.
Green Party leader Trevor Sargent said Mr Ahern looked to be on his last legs.
"It has become increasingly clear that the Taoiseach may not be fit for office. Next Tuesday in the Dáil he will have a final opportunity to explain himself and address the outstanding issues surrounding his political judgement.
"The Taoiseach has failed to reconcile his own position with his claim that it is wrong for a politician to be financially beholden to any individual. The continuation of the current state of affairs is damaging both to the country and to the government," Mr Sargent said.