Irish Ferries is expected to lay off more staff today in response to industrial action in a row over plans to "outsource" employment on the Rosslare-Normandy route.
The company made 140 workers redundant yesterday on the first day of an all-out strike by SIPTU members angered at the cost-cutting move.
Irish Ferries has claimed that the move to employ cheaper labour is necessary to help it compete with other ferry firms and low-cost airlines.
Meanwhile, the Irish Road Haulage Association has warned that the strike action is already affecting trade as other ferry companies do not have enough spare capacity to take trucks left stranded by Irish Ferries.
Speaking about the action this morning, IRHA spokesman Jimmy Quinn said: "Last night alone in Holyhead, there were some 80 trucks left behind when the Sea Link ferry departed from the docks.
"Normally, they would have been all on Irish Ferries…there's going to be shops left in Dublin this morning with no goods on the shelves because the trucks didn't make the ferry."