The Tanaiste has welcomed the Irish Catholic Bishops' statement supporting the Nice Treaty.
Ms Harney, Minister for Enterprise, Trade and Employment, said the bishops' statement "will help people focus on the real opportunity for Ireland to share peace and prosperity with the peoples of Eastern Europe, who were oppressed under communist regimes".
The bishops said there seemed to be a stronger case for the treaty than against, and voting No would change the direction of Ireland's positive involvement in Europe.
Ms Harney asked if "we are going to give the peoples of Eastern Europe a chance for the sort of peace and prosperity we have enjoyed in Europe. Surely we in Ireland, who have only recently lifted ourselves out of emigration and unemployment, will not be the ones to hold up their progress."
Criticising the reaction to the bishops' statement by "left-wing opponents of the Nice Treaty" she said it showed "how little tolerance they have for anyone who doesn't agree with their wild views. I don't believe the Irish people will succumb to the scare-mongering of the hard left and of people who insist on crying wolf every time we have a referendum on the European matter."
The Minister of State for Education, Mr Willie O'Dea, said he could not understand how opponents of the Nice Treaty say it would create a two-tier Europe. A two-tier Europe already existed "east and west".
The Labour leader, Mr Ruairi Quinn, whose party supports the treaty, said that whatever sense of frustration people might feel about the "often remote and bureaucratic nature of the EU, no honest person can dispute the achievement in bringing peace to Western Europe.
"And whatever doubts people may have about the shortcomings of the Nice Treaty, people must ask themselves if these are sufficient grounds for denying the applicant countries the opportunity for orderly and rapid membership of the Union and the opportunities for peace this would bring."
The Irish Road Haulage Association (IRHA) has also announced it would be urging members to vote Yes. The IRHA chief executive, Mr David Walsh, said an enlarged Europe would be of great benefit to Irish hauliers. This opportunity should be grasped.
