The Marine Minister, Pat 'The Cope' Gallagher, has said he is very concerned about the possibility of further escalation in the industrial dispute at Irish Ferries.
The minister said any further disruption would have serious effects for trade in and out of Ireland and such a scenario would have a hugely damaging impact in the run up to Christmas.
SIPTU has served notice on Irish Ferries of an indefinite strike, due to begin on Monday.
None of the company's ferry services are operating today due to the union's 24-hour stoppage over the company's plans to outsource 150 jobs on its Rosslare to Cherbourg route.
The union says it is escalating its action because the company has proceeded to hire agency workers on the MV Normandy, which is currently berthed in Belfast for maintenance work.
The workers began the one-day stoppage at 6.30am this morning.
Irish Ferries in bid to cut payroll costs
Earlier this year, Irish Ferries agreed cost savings of over €3m with SIPTU and the Seamen's Union of Ireland in order to remain competitive against their rivals.
The company plans to cut payroll costs by a further €3.5 million a year with the MV Normandy staff outsourcing.
Most staff have accepted a redundancy package, and the rest will be redeployed.
But SIPTU fears that that, once conceded, the principle of outsourcing will spread to other routes.
The company says it is making alternative arrangements for passengers, and will compensate them for any additional cost.
Intending customers can phone 0818 300 400 for further information.
Hauliers condemn action at Irish Ferries
The Irish Road Haulage Association has condemned next week's threatened strike as grossly irresponsible.
IRHA spokesperson Jimmy Quinn said November and December were peak shipping months, with a huge demand for consumer goods in the run-up to Christmas.
He warned that the strike would have huge economic consequences.
Mr Quinn said hauliers did not have many options in travelling to the UK, because of limited capacity on the Irish Sea and said SIPTU's strike would also interrupt transit to Europe.
He called for urgent action to resolve the row at Irish Ferries.
