Rejecting it would bar Ireland from emergency EU funding when its current bailout package expires in 2013.

Ireland is the only EU state putting it to a national vote but only 12 of the 17 eurozone members need to ratify it, so a "No" would not block the treaty.

The turnout was low and results are not expected until late on Friday.

As polling stations closed, PA reported that in Dublin 38% of the electorate voted while in the north-west counties just 20% took part.

The BBC's Mark Simpson, in Dublin, says the "Yes" camp feared people, angry with continuing austerity measures, would vote against the treaty to punish the government.

One man who voted "no" was Gerard Cunningham - he told the Associated Press: "Banks in Germany and Britain and elsewhere were just as responsible for the mess we're in. We're sick to the back teeth of being told it's all our own fault."

Another voter, Bridget Connolly voted "yes" on the grounds that "the treaty will solve nothing, but... we're going to need European money next year, plain and simple. We can't afford to be thumbing our noses at Europe right now".

'No to austerity' 

The pact, signed by all EU members except the Czech Republic and the UK, allows EU member states to co-ordinate their budget policies and impose penalties on rule-breakers.

It commits all ratifying members to achieve budget deficits of less than 0.5% of economic output.

Last year, Ireland's deficit reached 13.1%.

The country's 3.1m voters have twice rejected European Union treaties - in referendums in 2001 and 2008 - though both votes were overturned in subsequent polls.

Those against the treaty argue that austerity is not working and suggest that the country should instead default on debts at five nationalised banks.  

In a nationwide television address before campaigning ended, the Irish Prime Minister, Enda Kenny, urged people to vote in favour of the treaty.

"I ask you to make a further contribution by coming out to vote 'Yes' on Thursday," the taoiseach said.

"Yes to stability. Yes to investment. Yes to recovery. Yes to a working Ireland."

Sinn Fein President Gerry Adams, who is campaigning against the treaty, told voters not to be fooled.

"Be wise. Join with the millions across Europe who are demanding an end to austerity. On Thursday, vote 'No'."

The party's stance on the treaty has seen its support surge in recent weeks, making it the second most popular party in the Republic of Ireland for the first time. 

BBC