The Dublin Labour MEP, Mr Proinsias De Rossa, has accused the No lobby in the Nice referendum of distorting the position relating to qualified majority voting.
"They are trying to portray the situation, where no one member-state has a blocking vote, as a major dilution of Irish sovereignty and one of the main reasons to vote against Nice," he said.
"Some even give the impression that Ireland is losing the veto for the first time, ignoring the fact that the EU first began adopting decisions by qualified majority voting more than 15 years ago.
"The fact is that qualified majority voting is a creative instrument, which enables Europe to act, while the veto is a negative blocking instrument which prevents progress."
Mr De Rossa said it was "deeply regrettable" that those who claimed to be socialist would deliberately ignore the decisive contribution which qualified majority voting had made to European social and environmental policy over the past 15 years.
The Minister for Arts, Sport and Tourism, Mr O'Donoghue, said he welcomed the call made by the Irish Hotels Federation for a Yes vote.
"The IHF is just the latest business group to come out to highlight the massive opportunities presented by the treaty to safeguard existing jobs and to create thousands of more posts," he added.
"The loud call from the federation again underlines that all those who create jobs are calling for a Yes vote which will give Irish businesses access to new markets with over 100 million customers."
The Tánaiste, Ms Harney, said that a Yes vote would help keep taxes low. "Our tax policies are central to what our party stands for, as is our commitment to Europe.
Everyone knows our party is particularly vigilant about tax issues," she added.
"That is one reason why we are recommending a Yes vote to the Nice Treaty. Our national tax position is fully secured in the treaty. A Yes vote will endorse and strengthen this position for Ireland and for Europe."
The chairman of the Green Party, Mr John Gormley, claimed there was a note of desperation creeping into the Yes campaign.
"The Yes side knows that once the public is fully aware of the treaty's contents, they will lose," he added. "Their strategy, therefore, is to frighten and intimidate. To see normally responsible people behave like political bootboys is not a pretty sight."
Mr Gormley claimed that the rule book had been thrown out and it was now open season on the No side.
"If one ever had any illusions about how official Ireland works, they are now seeing the terrible reality unfold. What it reveals is the growing gap between the elite, consisting of such groups as the political parties, media, unions, IBEC and the ordinary people," he said.