Irish No campaigners seem to have gained ground
Irish and EU officials say they are confident the EU reform treaty will pass an Irish referendum despite a poll suggesting the No vote is surging.
A survey published by the Irish Times on Friday suggested 35% of people would vote No - more than twice the figure polled two weeks ago - against 30% Yes.
It is the first poll to put the Nos in the lead, ahead of Thursday's vote.
Ireland is the only country holding a referendum on the treaty. A No vote would throw the process into chaos.
The other 26 members of the EU are using parliamentary votes to ratify the Lisbon Treaty but Ireland is obliged to hold a referendum because it involves changing the constitution.
All 27 must ratify the treaty, which is meant to streamline decision-making processes in the EU, for it to come into effect next year, as planned.
Friday's TNS/mrbi poll suggested 28% of voters were still undecided, while 7% say they will not take part at all.
Irish Prime Minister Brian Cowen, who has led the Yes campaign, said he was confident of getting public approval.
But he said a No vote would have "dire consequences".
He blamed the latest poll figure on opponents "raising fears... creating suspicions".
Slovenian Foreign Minister Dimitrij Rupel, whose country holds the EU's rotating presidency, said: "I still believe that the Irish referendum will succeed."
EU commission head Jose Manuel Barroso did not comment directly on the poll but his spokesman said "it is very important for the Irish people to use their right to vote".
The Yes camp fears a low turnout will play into the hands of their opponents, with No supporters more strongly motivated to vote.
No campaigners said they were not getting carried away by the results.
Declan Ganley, the businessman heading the anti-treaty Libertas group, said the result "should be taken with a grain of salt".
"There are five full days of campaigning still to go in this campaign and the referendum is still there for the taking by either side," he said.
Mary Lou McDonald, an MEP for Sinn Fein, which opposes the treaty, insisted it could be negotiated if it is rejected.
"I believe the government can secure a better deal," she said.
But Finance Minister Brian Lenihan warned that there was "no plan B" if the treaty was derailed.