Irish Ferries has suspended all sailings between the UK and Ireland.
Trade union representatives last night discussed possible ways of escalating the dispute as managment and crew began a stand-off over company plans to outsource jobs.
Four ships' officers are continuing to barricade themselves into the control room of the Isle of Inishmore at Pembroke, while crews attached to the Ulysses and the Jonathan Swift are threatening to take similar action if the company tries to sail with cheaper agency staff.
Yesterday the Taoiseach, Mr Ahern criticised the way the company had handled the redundancy dispute.
This is a retrograde step by them, this is not in line with Irish industrial relations, they are trying to turn back the clock, they should still think about it, about everything that they have done in their handling of this. I fundamentally and totally disagree with [it]," he said.
Meanwhile, Ictu is to hold a meeting on Tuesday morning to discuss the ongoing dispute.
The meeting is being arranged following Siptu president Jack O'Connor's call to hold rallies nationwide next Friday, December 2nd, to support Irish Ferries workers.
Mr O'Connor said the dispute represented a defining moment for workers, employers, government and every citizen about the type of society in which they wished to live.