The continuing Luas row had caused an apparent rift within the Labour Party last night, as the leadership distanced itself from comments by its public enterprise spokesman on the party's future involvement in government.
Mr Emmet Stagg had said Labour would not enter coalition with Fianna Fail after the next general election if the main Government party continued to support the light rail plan unveiled on Tuesday.
But his party declined official comment on his remarks, and sources said the matter might be raised at today's meeting of the parliamentary party.
Mr Stagg said last night it was "inconceivable" that his party would go into government with anyone who did not support an adequate public transport system for Dublin.
Dismissing the plan unveiled this week as a "wish list" which was designed to kill off the Luas concept, he said Labour would insist on the reinstatement of something close to the original light rail plan by any coalition in which it was involved.
But he said his stance would not cause major problems in negotiations for the next government, because nothing would have happened in the meantime. "There won't be a spoonful of Dublin earth dug in the next five years," he said.
He also produced copies of the Dail record from November 12th last year in which the Minister for Public Enterprise, Ms O'Rourke, twice stated the Government would implement the recommendation of the Atkins study.
In one of these, Ms O'Rourke says: "If the study concludes in favour of the overground option, tight as the timetable may be, the EU money earmarked for Luas will go to Luas."
In the second, she says that "regardless of the outcome of the consultancy study, we will engage in the project recommended by it".
Mr Stagg added that, while he didn't want to "let Mary O'Rourke off that easily" from responsibility for this week's decision, he foresaw no problem in having the decision reversed by a new government. "Both the major parties we were in government with before supported the original Luas plan."
The Green MEP, Ms Patricia McKenna, said an analysis of the figures involved showed the Government's decision this week was "based entirely on the influence of a small number of businesses in the city centre and has nothing to do with democracy or what is best for the capital".
Compared with the cost of the overground option, for which the EU contribution would have reduced the total cost to the taxpayer to £149 million, the real cost of the new option would be more than £1,100 million, she said.
This included the estimated £450 million loss to south Dublin businesses for having to wait an extra three years for a modern light rail system; and up to £160 million extra, depending on the results of geological surveys.
It did not include the "huge cost of interim solutions to keep the traffic crisis at bay", she said. "So when Mary O'Rourke says that the cost of the project will be `£400 million plus', she shows she is obviously more economical with the truth than with taxpayers' money."
Dublin Corporation welcomed the decision on the revised plan, calling it "another milestone in the DTI strategy".
But the chairman of South Dublin County Council, Mr Eamonn Walsh, said it condemned the city to "continued road traffic chaos".
