Fine Gael's deputy leader tonight said those opposing the Nice treaty tended "to be on the extremes of every political issue".
Speaking in Ennis this evening, Mr Jim Mitchell, said no economic argument had been leveled against the treaty.
"None of the doomsday scenarios which they have painted on every occasion in the past have come to pass. Ireland itself joining the EU had only 50 per cent of the average per capita income. Today we have 106 per cent," he said.
He continued it would be to our economic advantage to give the same opportunity to other counties like Poland and Hungary.
"Ireland was held back for too long by closed minds. Political openness has served us well and is a key part of our, now abundant, national confidence. To vote No to the Nice treaty would be a betrayal of that confidence and openness," he added.