The Dublin North TD, Mr G.V. Wright, last night came under increasing pressure to break his silence and clarify his position regarding conflicting statements about money he received from the Cork property developer, Mr Owen O'Callaghan.
The Labour Party called on the Taoiseach to resolve the issue and to determine the facts surrounding the donation.
The junior partners in Government, the Progressive Democrats, also said they would like to see the matter "clarified".
Mr Wright told two members of the Fianna Fail inquiry team yesterday that he stood by what he told the committee: that he received money from Mr O'Callaghan for election expenses in the early 1990s, but did not solicit this money. However, Mr O'Callaghan insisted yesterday that a donation was solicited directly by the TD.
"There is a clear conflict between the published Fianna Fail report and the statement issued by the property developer, Owen O'Callaghan," said the Labour Party deputy leader, Mr Brendan Howlin.
"This report was initiated and received by the Taoiseach. Is he going to address the serious conflict of evidence that has arisen in respect of Deputy Wright's evidence?" Mr Howlin said the Taoiseach had a duty to determine the facts surrounding the donations.
"He cannot continue to act like a bystander or casual observer of events around him. There is a serious crisis afflicting the body politic. It requires urgent action."
The PDs expressed concern at the contradiction between Mr O'Callaghan and Mr Wright and said the matter needed clarification.
The PD Minister of State, Mr Robert Molloy, stressed that it was a matter in the first instance for Fianna Fail.
"We recognise that the tribunals are there and I think personally that is the right place for all these matters to be adjudicated upon, where the people who are being asked to answer questions will have an opportunity to do so."
In a statement to The Irish Times last night, Mr O'Callaghan reiterated that Mr Wright made an approach to him for an electoral contribution.
"I can accept that he may have no recollection of having made the approach but I have to reiterate that an approach was made to me," he said.
Mr O'Callaghan said that there was nothing wrong in this approach and said it was not linked in the slightest way to any vote on the Quarryvale project, which was supported from the outset by Mr Wright.
The Fine Gael frontbench spokesman, Mr Jim O'Keeffe, said yesterday the credentials of the Progressive Democrats would now come under more intensive scrutiny.
"They recently issued dire warnings about participating in a Government that required the support of Fianna Fail members who had questions to answer. They are now at that crossroads.
"This lame-duck government is now limping and it is not conducive to stability in circumstances where many important decisions have to be taken for the sake of the country," Mr O'Keeffe added.