Tánaiste Leo Varadkar has described the sacking without notice of 800 workers by P&O Ferries as "appalling".
Mr Varadkar, who is also Minister for Employment, said such a mass sacking would not happen under Irish/EU law as there is a transfer of undertakings (TUPE) in Ireland which means new workers have to get the same terms and condition as the old ones.
Mr Varadkar said he and the Minister for Transport Eamon Ryan are examining what options the Irish Government has to respond but said they are likely limited.
"Unfortunately shipping companies can get out of these things as they can reflag ships. You saw that with Irish Ferries [2005] some years ago."
At least 60 of the employees sacked by P&O Ferries on Thursday are from Ireland, their trade union has stated.
Mickey Smyth, an official with the maritime union, Nautilus International, said he estimated that 25 workers from the Republic and 35 from the North were among those dismissed.
Most worked on the European Causeway vessel which sails between Larne in Northern Ireland and Cairnryan, Scotland.
The workers affected were employed by an agency in Jersey and are subject to UK law.
Mr Smyth said the workers on the P&O Ferries vessel sailing between Liverpool and Dublin were not affected as they are employed under Dutch law.
The company said services between Liverpool and Dublin resumed on Saturday
The Dublin-Liverpool route is serviced by two roll-on, roll-off passenger and freight ships, the Bermuda-flagged Norbay and the Dutch-flagged Norbank.
“The Dutch obviously have different employment laws and they are protected. It is not part of the dispute. The other vessels are chartered vessels which are impacted,” Mr Smyth said.
Mr Smyth said he hoped the Irish Government would intervene in an effort to persuade P&O Ferries to change its mind.
Restructuring
According to The Sunday Times, British ministers knew in advance that P&O Ferries was planning to sack the workers.
According to a briefing document, Whitehall officials had told ministers it would "ensure that they remain a key player in the UK market for years to come through restructuring", a leaked memo shows.
The briefing document shows the UK Department for Transport failed to challenge the company’s decision to dismiss crew members with immediate effect, possibly in breach of employment law.
Written by a senior official, it was shared across the government, including with the prime minister’s private office, before P&O told staff in a video recording on Thursday that it was their final day at the company.
Unions and many Labour MPs have called for a boycott of the company.
Liverpool West Derby MP Ian Byrne tweeted: "I'm sure the good folk of Liverpool and Dublin will boycott this scab vessel if it restarts today. A huge test for this government as well, deeds not words please."
