The Commission President, Mr Romano Prodi, has described Ireland's referendum on the Nice Treaty as the final obstacle on the road to EU enlargement.
Mr Prodi told a meeting of EU foreign and European affairs ministers in Brussels that he hoped "our Irish friends would do everything to ensure that this final obstacle is overcome".
The Minister of State for European Affairs, Mr Dick Roche, said that Mr Prodi's remarks underlined the fact that the planned enlargement is not possible without Nice.
"These comments completely negate - yet again, for the umpteenth time - the myth propogated by the No side that somehow enlargement can proceed as currently envisaged and planned without Ireland voting Yes," he said.
The Commission President said last year that enlargement was legally possible without Nice. But he insisted later that the treaty was a political prerequisite for accepting up to 10 new member-states.
Mr Roche briefed the meeting on the steps the Government has taken to prepare for a second referendum, including last week's publication of a White Paper on the Nice Treaty. He said that a number of Ministers had expressed concern about the consequences of a second No vote.
Mr Roche said that the Government was making a better case for the treaty than during last year's referendum campaign.
And he said that most voters were not concerned that enlargement would produce an influx of immigrants from central and eastern Europe.
"There is an attempt to inject it into the campaign. It is not an issue to the fore in people's minds," he said.
Yesterday's meeting also agreed to extend an assets freeze and visa ban imposed in February on Zimbabwe's President, Mr Robert Mugabe, and his senior colleagues. The sanctions will now apply to members of the Zanu-PF politburo, all cabinet ministers and deputy ministers and some senior officials.