The Government have been attacked for "playing fast and loose" with taxpayers' money by allowing broadband and other projects go billions over budget.
Fianna Fáil leader Micheál Martin said the National Development Plan is now "in shreds" and Finance Minister Paschal Donohoe can no longer say he will find the extra money for spiralling costs of rural broadband, the national children's hospital and the proposed metro in Dublin.
He hit out at the Government for now spending almost €10bn on these three projects that are all significantly over budget.
"What the ministers and the Government are announcing is not grounded in reality," Mr Martin said of the Cabinet decision to press ahead with the consortium led by David McCourt to deliver the National Broadband Plan (NBP) which will now cost €5bn.
"There is a real world that the Department officials are grappling with in terms of how much is being spent each year and then there is this other planet where Ministers are announcing billions for this and billions for that.
"I don't think we are getting a real story on the National Development Plan, they are saying we will find the extra money. Either it suggests that they weren't telling the truth in terms of the National Development Plan and all the projections that are in there or an awful lot of the projects that are in there will never see the light of day over the next two decades," said Mr Martin.
He said his party are in favour of setting up an agency within the ESB to deliver broadband.
Referring to an increasing number of projects which are now billions over initial estimates, Mr Martin said the credibility of the National Development Plan, has been "torn to shreds".
"You have the children's hospital ballooning to €2bn, you have a broadband plan ballooning to €3bn and the Department saying we are going to have to find €1bn in the next three or four years to look after about 1,500 social houses, hundreds of primary schools, a range of other services in health, primary care centres."
He also pointed to the Taoiseach who said the new Metro will be €5bn, which he said was another €1.5bn to €2bn extra.
"What kind of planet are they living on? You are up to nearly €10bn on three projects, the National Development Plan has absolutely no credibility as we speak here today, no credibility," he said.
Mr Martin said the words "unprecedented risk" used by Department of Public Expenditure Secretary-General Robert Watt in his warnings on the broadband project was "heavy stuff" and said he was "taken aback by the lack of robust response to it" from the Government.
However, he said "now is not the time" for a General Election given the Brexit volatility.