The union representing the majority of Irish Ferries' seafarers has called for both sides in the dispute to begin moves towards a resolution.
As the stand-off between the company and Siptu ships officers continued, the Seamen's Union of Ireland (SUI) expressed the fear that a redundancy package on offer to members would be withdrawn. The SUI represents the vast majority of ratings on the company's vessels, and more than 60 per cent of its seafarers overall.
All of the company's services remained suspended yesterday, six days after the crisis began when security personnel disguised as passengers boarded two of its ships.
Agency staff from eastern Europe later arrived on the vessels, the Isle of Inishmore and the Ulysses, to begin "familiarisation programmes". They are due to replace existing seafarers who have accepted a redundancy package.
Attempts by the Labour Relations Commission to establish a basis for talks were continuing last night but with no sign of an end to the stalemate.
SUI general secretary Robert Carrick said his members were co-operating with the process of familiarising the agency recruits with the two vessels. They feared, however, that the dispute between the company and Siptu would result in them losing a redundancy offer of eight weeks pay per year of service.
This was because the redundancy offer had been conditional on two things: co-operation with the change to agency crews and there being no industrial action.
The company's human resources director, Alf McGrath, said last night that the redundancy offer was still on the table.
Mr Carrick said he feared the dispute "could end very badly", given that both sides were "so entrenched".
"Somebody needs to intervene, possibly the Taoiseach, and make both sides take a step back. The big fear is that otherwise the company will just close down," he said.
Mr Carrick said 90 per cent of SUI members had applied for redundancy, but some would not have done so but for the fact that "a gun was put to their heads".
Mr Carrick said the SUI was in dispute with the company over its refusal to accept Labour Court recommendations, but had not threatened industrial action.
Meanwhile, officers on board the Ulysses said yesterday the company's decision to remove security personnel from the ship on Tuesday was welcome but it did not address the underlying cause of the dispute, which has seen the ship stranded in Holyhead for the last week.
For the first time yesterday a number of officers on board the Ulysses at Holyhead were allowed to leave the ship to meet representatives of British trade union Numast.
Meanwhile, Irish Ferries was last night expected to bring new crew from Ireland to relieve ratings - non-officer ranks - on the Isle of Inishmore in Pembroke. Most of the officers on the vessel were relieved by Irish colleagues on Tuesday.
The four engineering officers barricaded in the control room have said that they will remain there until advised by their union, Siptu, in Dublin.
Many of the ship's key functions are managed from the control room and, while the officers remain inside it, the vessel cannot move.
It is understood the officers want inspectors from the International Transport Federation, the UK Maritime and Coastguard Agency and local police to certify that no damage has been caused to the ship, as part of any overall settlement.
Siptu members at Dublin Port, meanwhile, voted yesterday to support their seafaring colleagues by refusing to handle any Irish Ferries ships until the dispute is resolved.
The Irish Road Haulage Association said members were becoming "severely affected" by the dispute.