Two main players in the EU Fiscal Treaty campaign claimed they have scraped a win in the referendum despite being on opposite sides.
Taoiseach Enda Kenny and Libertas founder Declan Ganley both claimed victory during the final days of campaigning ahead of Thursday's controversial vote.
Mr Kenny admitted he was confident, but not overconfident, that the result would swing to the Yes side.
"No referendum or no election is won until all the votes are counted," he said.
"As far as I'm concerned we are going to keep this up until the close of polls.
"This is a choice of the people now and we've tried to explain to every issue about what's in this treaty and what's not in it."
But Mr Ganley said while it was too close to call he believed there would be a win for the No side.
"The austerity argument is something that is relevant to everybody because everybody is feeling it either directly, or a member of their family or friends are feeling it directly," he said.
"The fact that everybody in this country knows that our banks are sort of paralysed and that this bank debt is killing us.
"And everybody knows that Enda couldn't negotiate his way out of a wet paper bag."
More than 3.1 million people are eligible to vote when polls open nationwide on Thursday - but less than 60% of those eligible turned out to vote on the Nice and Lisbon treaties.
Voting got under way on the islands off the west coast of Ireland yesterday, with residents on Inishturk, Inishbiggle and Clare Island at the polls today.
Another 1,164 are due to vote on Inishmore, Inishmaan, Inisheer and Inishbofin, off Galway, tomorrow and islanders off the south-west of Cork will vote when polling stations open nationwide on Thursday morning.
A broadcast moratorium on referendum content starts tomorrow afternoon.
Three recent opinion polls revealed a 60/40 split in favour of the European Fiscal Treaty.
Mr Kenny called on every citizen who feels for their country to vote Yes and send a clear confident message around the world.
"This treaty is about confidence, about investment, about opportunity, about stability and about good housekeeping," he added.
He claimed the No campaign had peddled myths, falses and untruths stressing the treaty had nothing to do with corporation or financial transaction tax. He also maintained intensive negations on the bank debt were ongoing separately.
But campaigners on the No side accused the Government of lying through its teeth over the state of the country's finances.
Richard Boyd Barrett, of the United Left Alliance (ULA), argued the country's deficit of €18bn would fall to €3.1bn next year if bank debts and other interest on debt are not paid.
"This is a gap that could easily be filled and more by increasing income tax on those earning over €150,000 per year and by imposing a modest wealth tax on the wealth and assets of the wealthiest 5% of the population," he said.
"So contrary to what the Government claim, we would have the money to pay nurses, pensions, social welfare and all the things we actually need.
"We just wouldn't have the money to pay-off bankers gambling debts and debt interest."
But Fianna Fáil leader Micheál Martin said ratifying the treaty is the only secure way for Ireland to access vital long-term funding for public services.
"In spite of the negative and cynical campaigns of the main parties against the treaty the central fact has remained that a No vote is a vote for greater uncertainty and austerity," he said.
"Over the next two days we will keep working for a Yes vote."
Elsewhere the High Court will hear a legal challenge by Sinn Féin against the Referendum Commission's assertion that the opportunity for a veto on the European Stability Mechanism was now gone.
"This is a matter of central importance to the referendum," said party president Gerry Adams.
"We are looking for the Referendum Commission to acknowledge that the Government is legally at liberty to withhold ratification of the Article 136 amendment to the EU treaties."