Irish Ferries has refused an invitation by the Labour Court to attend talks aimed at resolving the current dispute over the its redundancy plan.
The company - which was unavailable for comment this evening - is seeking to replace all 543 Irish staff with cheaper agency staff from Eastern Europe as part of a drastic cost-cutting exercise.
In a statement today, Irish Ferries said it had no alternative to implementing the cost-cutting measures.
The company said it was unable to continue operations at it current high cost base. It blamed low-cost competition and low-fares airlines. Staff who choose to stay on will have to accept lower pay and conditions.
Earlier Siptu president Jack O'Connor warned that if social partnership fails to protect workers at Irish Ferries, the union's participation in future deals would be rendered "pointless".
Mr O'Connor said this was "not a case of a company clinging to survival but one of naked, unblemished greed".
At a meeting in Dublin of the International Transport Workers' Federation - of which Siptu is an affiliate - Mr O'Connor described the current dispute at Irish Ferries as the "most significant crisis" that the social partnership process has faced in its 18-year history.
He said: "If the partnership was not capable of protecting minimum standards or preventing the replacement of workers by vulnerable people on €3 an hour then there is no point in the trade union being involved in it."
The company claims the Irish Sea cars market has fallen by 9 per cent this year and fuel had gone up in price by 50 per cent.
It warned it would become unprofitable by the end of 2007 another 250 shore-based jobs would be lost if it did not act now.
But Mr O'Connor claimed the company's share of freight trade in the Irish Sea had not diminished and that the market itself had expanded by 25 per cent in last five years.
Mr O'Connor said a consultants' report if implemented could deliver to the company three-quarters of the €20 million in savings it claims to need.
Yesterday the Taoiseach described company's plan as "sharp practice and totally unacceptable".
Mr Ahern also questioned the legality of the company's plan and said that the Government had sought legal advice on the matter.
In its statement, Irish Ferries acknowledged the Taoiseach's concerns, accepting they were "real and genuine". But it also claimed some 70 per cent of voluntary redundancy packages had been taken up by staff.
He called on the Government to intervene to protect Irish maritime workers' jobs.
The redundancy package offers workers up to eight weeks' pay per year of service with no cap. This is likely to prove attractive to a large number of workers, some of whom stand to receive more than €200,000.
But although the Seamen's Union of Ireland accepts many workers may opt to take redundancy, a spokesman said it was far from a voluntary severance package. "The company is basically saying take this or get out," he said.