The PDs yesterday made a stinging attack on the Railway Procurement Agency (RPA), claiming the State body was not up to the job of building a metro in Dublin.
The attack by the party's transport spokesman, Senator Tom Morrissey, follows criticisms by the Fianna Fáil TD Mr Eoin Ryan, who chairs the Joint Oireachtas Committee on Transport.
Both remarks are believed to reflect unease within the Government over the credibility of the RPA, which has reduced its budget projection for a metro by €1.4 billion to €3.4 billion.
The RPA, which is responsible for Luas, was set up two years ago to remove the management of new rail initiatives from CIÉ. While the Minister for Transport, Mr Brennan, has indicated he will bring proposals for a metro to the Cabinet within weeks, Mr Morrissey said the latest RPA plan was not viable.
A Government spokeswoman added to the questioning of the RPA by saying that there were concerns about building costs and the perception Irish infrastructure cost more and took longer to build than similar schemes elsewhere.
Mr Morrissey was commenting on a new RPA metro plan which was submitted to the Government last week. This would link Dublin Airport with St Stephen's Green, via Ballymun, Dublin City University, the Botanic Gardens, the Mater Hospital, O'Connell Street and D'Olier Street.
Unlike the earlier more expensive plan, there will be no direct link with the DART suburban rail system at Tara Street and Pearse Station. However, passengers would go to Tara Street from D'Olier Street via an underground travelator.
Mr Morrissey said the logic of by-passing key city railway stations should be questioned, and called for another RPA review of its plans. He called for a formal partnership with the Madrid metro company which built an extensive underground system in record time at minimal cost.
When asked whether he was implying that the RPA were not able for the job, he said: "That is correct." Mr Morrissey said he spoke for the PDs on the issue.
Mr Ryan moved earlier to question the RPA by writing on June 9th to its chief executive, Mr Frank Allen, asking 25 questions of the agency.
Among other details he sought a statement of the number of professionally-qualified staff at the agency, and the nature of their qualifications and experience.
Mr Ryan's views are believed to reflect thinking at senior levels in Fianna Fáil. He said yesterday: "What I'm saying, and I think the committee is saying, is that there are serious questions around how we could suddenly lob €1.4 billion off the projection."
The comments by Mr Morrissey and Mr Ryan reflect what some sources say is a sense of "bemusement" among certain Ministers at the manner in which the RPA reduced its cost projections for the Dublin initiative.
The head of corporate services at the RPA, Mr Ger Hannon, defended its plans. "In a sense we should be applauded for going out on day one for an overall realistic cost for something which isn't honed back to a bare minimum."