Irish Ferries, a subsidiary of Dublin-based Irish Continental Group PLC, earlier this year offered its 543 unionized workers on its main Britain-Ireland routes payoffs worth 25 million euros ($30 million) if they quit voluntarily.

But when the company two weeks ago began introducing new workers, chiefly from Latvia _ who were willing to work for 3.60 euros ($4.25) an hour, less than half of Ireland's minimum wage _ union chiefs seized control of two ships, forcing the company to shut down services at an estimated loss of 2 million euros ($2.5 million) a day.

The government-appointed Labor Relations Commission brokered three days of negotiations this week, but failed to reach a deal. Irish Ferries insists it's legal for an international shipping company to ignore Ireland's minimum wage, and has applied to register its ships in Cyprus to increase its leverage on the issue.

The government has harshly criticized Irish Ferries and pushed, so far in vain, for a mediated compromise.

"It is not acceptable that you can displace Irish workers for people who would be paid much less than the minimum wage," Irish Prime Minister Bertie Ahern said in London.

"I cannot force the management and ownership of Irish Ferries to do what I would like them to do," Ahern added.

The Irish Congress of Trade Unions, which represents more than 700,000 workers in this country of 4 million, backed Friday's protests in support of its largest member _ the Services, Industrial, Professional & Technical Union, or SIPTU, which has 200,000 members and represents most Irish Ferries employees.

Members of several unions, including teachers and bus drivers, gathered in Dublin's Parnell Square, the home of several labor-union headquarters, for a march across the River Liffey to the parliament building, Leinster House.

Many carried placards said that read, "Stop outsourcing," a reference to the increasing practice of hiring low-paid immigrants from Eastern European states. More than 150,000 workers from the European Union's most recently admitted states, chiefly Poland and Latvia, have taken up jobs in Ireland in the past 18 months and are prominent in restaurants and pubs, and on construction sites and farms.

David Begg, secretary-general of the union congress, rejected accusations that the protesters were hostile to immigration. He said unionized workers wanted to stop "the suppression of wage rates in this country."

But business leaders warned that Irish Ferries might choose to fold its business and lease its four ships to another company, and pay its laid-off workers only a fraction of the current amount on offer.

"Those organizing this march have lost sight of the real world," Turlough O'Sullivan, director-general of the Irish Business and Employers Federation, wrote in Friday's Irish Times newspaper. "They are right that their members are under threat ... from those who are producing similar goods and services in other countries and selling them at a cheaper price."

He said employee pay was rising unsustainably at more than triple the rate of business profits in Ireland, where wages had grown on average 70 percent over the past 10 years compared to an EU average of 28 percent. He said the average employee in Ireland cost employers 38,100 euros ($45,000) last year, compared to 33,200 euros ($39,000) in Germany, 28,400 euros ($33,500) in Spain, 11,300 euros ($13,300) in Hungary and 7,700 euros ($9,100) in Poland.