TAOISEACH Enda Kenny has called the European fiscal treaty an insurance policy for Ireland and the children of the future.
As three major trade unions formed a formidable 'No' bloc, Mr Kenny urged voters to think about how they will guarantee their future in the May 31 referendum.
Unite, Mandate and the Technical Engineering and Electrical Union (TEEU) have dealt the coalition Government a major blow by refusing to support the pact.
"Ireland is in a programme for the next two years and will remain so. Nothing in the treaty changes that," the Taoiseach said in Mayo.
Mr Kenny said the decision for voters was whether they wanted to guarantee their future with an insurance policy that would allow Ireland to draw money from the European Stability Mechanism.
"It's like saying, 'look, I'm going to buy this house but I'd like to know that it's insured'," he said.
Sinn Fein president Gerry Adams insisted the Taoiseach's assessment was wrong.
"If Irish citizens reject the treaty, the State will not be excluded from future help from the European Stability Mechanism," Mr Adams said.
"This is an empty threat which has been referred to as a blackmail clause. This clause is not an article of the ESM treaty."
Mr Adams said a clause would ensure that no member state was denied funding if the wider stability of the eurozone was under threat.
The TEEU, with 40,000 members, announced its opposition after Siptu published a detailed document which portrayed the treaty as a one-sided austerity proposal and called for a huge stimulus package.
Meanwhile the executive of the Irish Congress of Trade Unions will meet tomorrow to decide its position.
Unite, which, along with Mandate, has 100,000 members, has said it will push Congress to speak with one voice against the treaty.
Jimmy Kelly, the union's regional secretary, accused promoters of the treaty of using scare tactics.
"We have lived as an experiment for the past three years and all we have to show for it is stifled growth, a disastrous rise in long-term unemployment and a fracturing of social cohesion," he said.
"There is talk of scare tactics and vague repercussions should we vote no.
"We will argue strongly first within the trade union community and then among the broader population that we cannot walk blindly into this surrender of the long-term right to determine our own future and the priorities we hold to be the strongest."
Eamon Devoy, TEEU general secretary, said the decision to call a No vote was not taken lightly.
"It is becoming increasingly obvious that austerity is not working. The right-wing agenda of Chancellor Merkel might make sense in Germany but it is a death sentence for our economy and people," he said.
Mr Devoy said the IMF had suggested that severe austerity is not the only solution to the economic crisis and he warned that it was senseless to vote on the treaty when a country as influential as France could change its stance.