Fianna Fáil backbencher Noel O'Flynn has called on the Taoiseach to make a public statement on the continuing controversy surrounding Mr Ahern's personal finances.
The TD for Cork North Central said he fully supported Mr Ahern but urged him to "clarify" a number of matters after new revelations in the Mahon tribunal last week.
Mr Ahern said yesterday he believed a £5,000 donation he received in 1993 as part of a £22,500 whip-around was from the personal funds of former managing director of NCB stockbrokers Padraic O'Connor.
Minister for Foreign Affairs Dermot Ahern
The Mahon tribunal heard last week that the payment was requested by former Fianna Fáil chief fundraiser Des Richardson and was made through a false invoice. However, Mr O'Connor maintains it was not a personal donation and that he was not a close friend of Mr Ahern.
Mr Ahern said it was wrong to use a false invoice but that it was "done between the two of them [Mr Richardson and Mr O'Connor] "
Speaking on RTÉ's Morning Irelandtoday, Mr O'Flynn said: "In order to clarify a number of issues it might be a good idead at this point in time for the Taoiseach to make a statement in relation to the events of last week."
"There are political implications for allegations that have been made and it may be in the public interest for him to make a statement.
Ciarán Lynch, Labour Party
"I want to make it clear that I fully support the Taoiseach and indeed am awaiting the outcome of due process and the outcome of the Mahon tribunal."
Minister for Foreign Affairs said he totally disagreed with Mr O'Flynn and that the vast majority of the parliamentary party was behind the Taoiseach. "I think people like Noel O'Flynn should settle down", he added.
Labour Party TD Ciarán Lynch said both Noel O'Flynn and Michael McGrath had been "less than fulsome in their praise of their boss in the last 24 hours or so". "And when you think that Ned O'Keeffe parted company with the Taoiseach last week, it all looks rather grim for Mr Ahern in Cork."
"This would reflect the unease felt by Fianna Fáil supporters over these revelations. Comments by the Taoiseach where the only consistency is their inconsistency, have simply served to muddy the water and have further damaged the Taoiseach's credibility to a massive extent," Mr Lynch said.
Yesterday Fianna Fáil MEP Eoin Ryan expressed his "total confidence" in Mr Ahern after a newspaper reported he had called for an internal Fianna Fail investigation into the Taoiseach.
Mr Ryan said the Irish Daily Mailreport was both "inaccurate and wrong".
Pressure on Mr Ahern is mounting in advance of his appearance at the Mahon tribunal in the week before Christmas.
He has dismissed claims that he gave implicit approval to the National Lottery to enter talks with Manchester businessman Norman Turner about becoming involved in his plans for a casino in Dublin. He is likely to face questions on the matter in the Dail today.
Mr Ahern was minister for finance at the time of the talks in the early 1990s and had political responsibility for the lottery.
The contacts did not lead to a formal deal between the lottery and Mr Turner's group Sonas, whose plans for the site of the former Phoenix Park racecourse were backed by US casino firm Ogden.
The rejection of the claims by Mr Ahern's spokesman conflicts with the account of former National Lottery chairman John Hynes, who said on Sunday night that he would not have entered talks without implicit approval.
