The taoiseach is at the centre of a new row over the cost of the national stadium.
Mr Ahern will face questions from Opposition leaders today in the Dail on the authenticity of figures given by the Government in May.
These did not include Department of Finance concerns of a possible overrun of £100 million.
Documents released under the Freedom of Information Act also showed the Department of Finance's doubts about private sector investment in the project.
The Fine Gael leader, Mr Michael Noonan, said serious questions had been cast over the authenticity of figures given in the Dail chamber in May by the Minister for Sport, Dr McDaid, and subsequently endorsed by Mr Ahern.
Mr Noonan said the document was written in February, but Dr McDaid "did not see fit" to mention the Department of Finance's concerns.
The Labour Party leader, Mr Ruairi Quinn, also questioned the figures and said the Taoiseach should end his campaign of "evasion and distortion" about the cost of Stadium Campus Ireland. He said Mr Ahern had become the worst advocate for his own project.
However, Mr Ahern said yesterday there was "absolutely nothing new" in the figures. He said the information released to RTE after an FOI request predated the Government's decision to undertake a review of costs.
"The FOI data is from an earlier period before we talked about the review so it is irrelevant to the debate," he said.
Sports Campus Ireland, including the new stadium and other sports facilities, has an estimated price tag of £550 million.
The memorandum written by Mr Bob Curran, former second secretary at the Department of Finance, for Mr McCreevy on February 22nd, raised serious questions about this estimate. It suggested that moving the State Laboratories from Abbotstown would cost almost £200 million.
It said the stadium costs of £231 million provided by Campus Stadium Ireland Development Ltd might now be an underestimate, and the figure was exclusive of VAT.
Since 1999, it pointed out, tender-price inflation could add about 25 per cent to building costs. "These additions alone would bring the feasibility study cost estimates for the stadium up to £323 million in current prices," it said.
The cost of infrastructure might also have been underestimated, it stated. An interchange on the M50 was priced at £3 million, but would actually cost four times as much.
The Department also raised doubts about whether commercial investment in the site would ever see a return.
CSID Ltd had indicated this would include hotels, restaurants, a combined heat and power plant and car and coach parking facilities.
"The cost of this element is put at £110 million but again this Department does not have an individual breakdown of the estimated cost of these projects."
"Apart from the private donation of £50 million (from Mr J.P. McManus), the Department does not have any information to enable it to evaluate the interest and likelihood of the private sector providing such finance," it stated.
It also said the Department did not have information on the "precise role" envisaged for the private sector in sporting and commercial activities. It was clear a commercial return was needed but "it is not clear where such a return will be obtained or at what level".
Mr Noonan said it was now clear that the Department of Finance's estimate of the true costs of project were much closer to Fine Gael's own figure of £1 billion. He called on the Taoiseach to make an immediate statement clarifying the Government's position.