DUBLIN, June 12: Ireland voted in a knife-edge referendum on the European Union's new reform treaty on Thursday, threatening to plunge the 27-nation bloc into new crisis if it is rejected.

Prime Minister Brian Cowen voiced confidence that the country's three million voters would back the Lisbon Treaty, despite recent opinion polls indicating that the result is too close to call.

“I'm happy, I've led it the very best way I possibly could, I did it from the front, I've gone all over the country, I've put the issues,” he told reporters. Asked if he was nervous, he said: “No, I'm confident.” But EU leaders are anxiously watching Ireland's voters after a late surge of opposition, despite an all-out “Yes” campaign led by Cowen and backed by all bar one of the main parties.

Ireland is the only EU member holding a public vote on the Lisbon Treaty, which replaced a draft EU constitution after its rejection by French and Dutch voters in 2005.

One poll last week put the “no” campaign ahead by 35 per cent against 30 per cent for those backing the treaty. At the weekend another survey predicted a narrow “yes” victory, by 42 per cent to 39 per cent.

Newspapers urged readers to make their voice heard, amid warnings that every vote will count.

The Irish Daily Star tabloid said the EU's “destiny is in our hands” while the Irish Times and the Irish Independent said the result had “momentous consequences” for both Ireland and Europe.

Some commentators said a low turnout could point to a “No” victory as “Yes” voters stay at home. By mid-afternoon turnout was “mixed,” according to state broadcaster RTE, at 18-20 per cent in several constituencies but as little as 12 per cent and as much as 40 per cent in others.

The Lisbon Treaty, which aims to make decision-making across the bloc more efficient following recent expansion, has already been approved through a parliamentary vote by 18 other European nations.

If it is rejected the EU risks being pitched into a new period of institutional limbo like that which followed the demise of the EU constitution three years ago. But many Irish say they do not see why they should support a document which they do not understand and which even Cowen admits he has not read cover-to-cover.

Many are also worried by claims from some in the “no” camp that the referendum will threaten Irish totems like military neutrality and the ban on abortion, claims strongly rejected by Cowen.

Declan Ganley, the businessman behind prominent opposition group Libertas, urged people to vote “no” so that Ireland could retain a stronger voice in Europe which he says would be wiped out by the treaty.

“I hope, and I firmly believe, that the Irish people will vote 'no' and that the work can immediately begin on constructing a better vision of Europe for all its 490 million citizens,” he said.

Few other EU leaders have commented on the Irish poll in recent days, reflecting concerns that such interventions could be counter-productive and fuel the “no” vote.

French Agriculture Minister Michel Barnier underlined Thursday that the issue was for Irish voters alone to decide. “The Irish are a responsible and sovereign people and I have confidence in them,” he said.

The Irish taoiseach (prime minister) made a last campaign push on Wednesday with a whirlwind tour of his home area of the Irish Midlands.

“At a time of growing economic uncertainty, it is in Ireland's vital national interest to have a reformed European Union working for it,” said Cowen, who only took over from Bertie Ahern as premier a month ago.

“After 35 years of respecting and helping Ireland, the EU has earned the right not to be seen as a threat to us.” Ireland has caused upsets in EU referendums before. In 2001, its voters rejected the Nice Treaty, a result overturned in a second poll the following year.

This time, though, Cowen insists there is “no plan B” in case of a rejection.

Polls were due to close 10:00 pm (2100 GMT) on Thursday. Vote counting will begin on Friday morning, with a result expected during the day.—AFP