The European Commission had given the "green light" to enlargement and the Irish electorate should do the same, the Minister for Transport, Mr Brennan, has told a Fianna Fáil news conference on the Nice referendum.
When asked about a statement attributed to the Czech Republic's chief EU negotiator that an Irish rejection of Nice would only delay enlargement by a few months, the Fianna Fáil TD, Mr Pat Carey said there would be "a long period of uncertainty" which would be "years, rather than months".
Mr Brennan said: "The Czech Government wants the Irish people to ratify this treaty."
He pointed to the recent joint statement issued in Warsaw by foreign ministers of ten applicant states, stressing the importance of ratifying Nice. Nice was "the mechanism that is in front of us". He had no doubt that "down the line", other mechanisms might be found but he did not think the people of Ireland would be forgiven for rejecting the treaty.
"It is a simple question to the people of Ireland." Voting No would be a "signal that we are going cold on Europe" and there would be "knock-on effects" on the economy. The Minister of State at the Department of Justice, Mr Willie O'Dea said, "It doesn't matter whether it is a couple of months or years, the damage will have been done." In his own region of the mid-west, one in every six jobs depended on foreign direct investment which would be jeopardised by a No vote.
Mr Carey said there was "widespread concern" among existing member-states and applicant states that a No vote would lead to attempts to "unpick" the treaty. Meanwhile, the progress report on the enlargement process by the European Commission has been welcomed by the Minister for Foreign Affairs, Mr Cowen, who said it "underlines for us in Ireland the significance of the decision we have to take in casting our vote on the Nice Treaty".
The Commission had concluded that ten countries met the requirements of membership: "Today's statement by the Commission clearly makes the claim of the No side that enlargement can proceed without the Nice Treaty totally redundant," Mr Cowen said.