The Minister for Social and Family Affairs denied that passing the Nice referendum would lead to an influx of migrants into the State.

Ms Coughlan accused the No lobby of trying to "fan the fears of a flood of emigrants swamping our shores, our labour markets and our social welfare system". This, she said, was a "desperate scaremongering tactic", which had no basis in fact and played to fears founded on ignorance.

"There is simply no evidence that a flood of migrants will come to Ireland. Past experience of the accession of new member-states to the European Union has shown that these fears were unfounded.

"For example, in the case of the accession of Greece in 1981, transitional arrangements were put in place, and, again, for Spain and Portugal in 1986. Despite this, fears of a major migration wave proved to be without foundation and there was very little change in the migration patterns from these countries." Ms Coughlan said that on the basis of the collective knowledge now available, potential migrants from the candidate countries were less likely to migrate to Ireland. They were more likely to migrate to neighbouring countries where a network of their migrants already existed.

Of real concern to Ireland, she said, was the need to attract workers with certain skills and the State was hopeful that full freedom of movement would enable it to meet its labour market needs.

"Workers with certain skills, hopefully, will come to Ireland to meet our labour market needs, but we will need these workers and will have to compete with other countries to attract them. Others whose skills are not in demand here will simply seek work elsewhere in an enlarged European community," she said.

The Fine Gael deputy leader and spokesman on finance, Mr Richard Bruton, said it galled him to see the cynical way some No campaigners sought to whip up panic that 75 million people would swarm Irish shores, becoming dependent on taxpayers.

"These people have smugly sleep-walked their way during the long history of Irish marginalisation from the economic opportunities, which condemned so many to leave family and community behind in search of work."

"It is the opportunities that EU membership offered that allowed us to staunch the haemorrhage of our brightest and best to foreign shores. A No vote, far from protecting the rest of Europe from an influx of migrants, would rather make migration all the more likely as these countries sink in their struggle to get economic development under way without the benefits of access to good markets." There would, he added, be temporary movement of workers from eastern European countries in pursuit of good job opportunities elsewhere in Europe. "Like Irish emigrants, since we joined the EU, those who do leave will make a great contribution in their host countries and will look forward to the opportunity of returning to their own country to help its economic development. This is not a process about which we should be hostile or fearful."

The Government Chief Whip, Ms Mary Hanafin, said the magnitude of the choices before the people could not be overstated. "Not only will we decide on our own destiny, we will adjudicate on the hopes and dreams of others.

"We will decide whether enlargement can proceed on schedule or not, thereby deciding whether the people of central and eastern Europe will enjoy the opportunities that have so empowered our workers, students, women, every member of Irish society."