The dramatic deterioration of Ireland’s economy may lead a majority of Irish voters who previously voted No in Ireland’s Lisbon Treaty referendum to reconsider and vote yes when polls open this Friday.

The challenge for the Irish government in the remaining few days will be to persuade people who previously who voted no to reconsider and also to secure support from undecided voters.

This week the government campaign appears to be working. The most recent Irish polls show that between 48% and 55% of Irish voters favor approval of the treaty, but there are still enough undecideds that the final result could be close.

In the weeks leading up to the crucial vote the Irish government has reiterated the point that Ireland’s economic fate is dependent on full European Union membership. On Monday Finance Minister Brian Lenihan told the press that a no vote would damage investor confidence in Ireland.

“This is very clear from all of the testimony we have from people who actually invest and create real sustainable jobs,” he said.

Lenihan added that Ireland couldn’t afford to be isolated from the rest of Europe at a time when the country’s economy is in crisis.

The controversial Lisbon Treaty is supposed to improve decision-making across the EU and also enhance its international profile, but it has been blocked since Ireland voted no last year. It has to be agreed by all 27-member states to come in to force.

Taoiseach (Prime Minister) Brian Cowen told the press that it was imperative that Ireland does not give the impression it is turning its back on Europe. “Friday’s referendum on the Lisbon Treaty will be a defining moment in the country’s destiny,” Cowen said.

“The road we choose will not only determine the shape of our economy, but define our place in the wider world and the destiny of this generation and our children’s generation for years to come.”

Meanwhile, 54 leading businesses and lobby groups offered their support for the yes campaign, claiming it was essential for Ireland’s economic recovery. The groups represent every major business organization in Ireland including the American Chamber of Commerce, Chambers Ireland, Irish Business Employers Confederation, Irish Exporters Association and the Small Firms Association.

On Monday Ryanair boss Michael O’Leary warned a no vote in the referendum would destroy the country’s economy. The famous airline chief called on the Irish electorate to separate their anger at the government on Friday -- but to vote them out if an early general election is called next year.

O’Leary said it was time Irish people woke up to the fact the county was bankrupt and needed Europe. “If we vote no the cost of borrowing will rise significantly, we will lose an EU commissioner because we go back to the Nice Treaty, and we will lose a veto on direct taxation,” he warned.

More than any sector of Irish society, Irish farmers have benefited from the Republic's membership of the EU, but last year a majority of them voted no to the Lisbon Treaty. How they will vote on Friday when Ireland reconsiders the treaty may well decide the balance of the vote.

The Irish Farmers Association (IFA) president Padraig Walshe, wants a strong yes showing from farmers this time. “We have a population of four million people, we produce enough food for about 24 million people. Access to the European market is crucial to us,” he said.

However James Reynolds, the chairman of the Farmers for No campaign, is canvassing against the treaty. Reynolds believes Lisbon threatens Ireland’s food industry and a possible 80,000 jobs.

“If we say yes to Lisbon, we will be giving a blank check to Brussels to abuse farmers, to force them to become dependent on hand-outs and subsidies,” Reynolds said. “A farmer who votes for Lisbon is in effect a turkey voting for Christmas.”