Anti-Nice campaigners have expressed "amazement" at the Taoiseach's accusation that they had been putting forward flawed arguments and "the same old dingbat stuff" for 30 years.
Mr Ahern said the No campaign was scaremongering and trying to arouse fear, but the only fear for Ireland was of a No vote. "That is where the damage is to our country. That is where the damage is to Ireland politically and socially," he said.
Mr Dan Boyle, the Green Party's finance spokesman, said he was amazed at the comments.
"Maybe surprise should not exist about the debating style of a man who has called opponents 'wafflers' and 'dimwits and eejits' in the past, and once suggested the people would be 'mad' to vote for the Green Party. Perhaps it is a measure of desperation of the Government's Yes campaign not taking effect, that the Taoiseach feels the need to have recourse to this type of behaviour," he claimed.
Speaking on RTÉ Radio yesterday, the Taoiseach said that every time he had asked the No side to give him the economic alternative to Nice "I have got a deathly silence and I will continue to get that.
"Because the arguments they have put forward for 30 years have always been flawed. And they use the same old dingbat stuff all of the time, but it's not us that is scaremongering, it is them."
However, Mr Justin Barrett, of the No to Nice Campaign, said the Taoiseach's comments were "spin". He had written to Mr Ahern, challenging him to a live television debate and "then he won't get a deathly silence".
Mr Barrett said a lot of the current issues were not around 30 years ago, including "enhanced co-operation and the the cost of enlargement in CAP reform for two million Polish farmers".
Mr Ahern said that if the people rejected Nice a second time, the EU applicant countries would see that "we have stabbed them in the back in their hour of need" while other members and people in the wider world would question Ireland's commitment to the European project.
Asked if people would oppose Nice in order to protest against Government cutbacks, he said the Irish people were intelligent and knew Nice was not about these things.
The Forum on Europe is holding a public meeting tonight in the Linen Hall Arts Centre, Castlebar, Co Mayo. at 8 p.m. with Prof Brigid Laffan and Mr Vincent Wood of Sinn Féin as speakers.