The stand-off on board the Irish Ferries vessel Isle of Inishmore in the Welsh port of Pembroke escalated for a time yesterday when a number of officers sealed off the access to the bridge for several hours.
It is understood that the officers changed the access codes for the bridge after Irish Ferries management sought to bring into the area a number of senior personnel from the replacement crew which the company wants to take over the running of the ship.
These are believed to have included a British captain and a number of deck officers from the replacement crew.
Chief engineer on the Isle of Inishmore, Gary Jones, told The Irish Times the bridge had been sealed off for several hours.
He said the row ended when Irish Ferries management indicated they would not seek to bring officers from the replacement crew on to the bridge.
However, Alf McGrath, head of human resources with Irish Ferries, said the company had no information about such an incident.
The International Transport Workers' Federation (ITWF) last night also said officers on the ship had sealed off the bridge for a time.
Mr Jones said the company had classified as "passengers" security personnel and replacement crew members brought on board by Irish Ferries on Thursday.
He said passengers were not allowed on to the bridge except at the invitation of the ship's master.
Mr Jones is one of four officers on The Isle of Inishmore who have been barricaded in the control room of the vessel for the last four days.
The four officers sealed themselves behind watertight doors in the control room, which is located below the water line, after a group of more than a dozen security staff hired by Irish Ferries made themselves known without warning.
Sources on the ship said one of these security personnel became ill and had been taken to hospital in Pembroke on Saturday night.
Mr Jones said morale among the crew was holding up, although there were some concerns about the contents of bags brought on board by the security personnel hired by the company. The crew did not know what was in them.
He said the four officers in the control room where still providing a professional service for the vessel.
"We control heating, lighting and sewerage systems. The other day we took on board 400 tonnes of fuel," he said.
He said that to date there had been no negotiations with Irish Ferries management to end the standoff.
The ferry port at Pembroke remained closed yesterday.
An electronic sign in the car park said Irish Ferries hoped the next scheduled service would be today at 2.30pm.
Mr Jones said he believed this was wishful thinking on behalf of the company.
A regular changeover of some crew from the vessel is scheduled to take place in Rosslare on Tuesday evening.
Yesterday, in a separate development, Irish Ferries refused to allow an inspector from the ITWF to go on board a second Irish Ferries vessel, The Ulysses, which has been stranded in Holyhead for several days as part of the ongoing dispute.
A federation inspector said Irish Ferries management in Holyhead had told him that permission for crew members to disembark from the vessel was being controlled.
A second inspector from the ITWF was due to arrive in Pembroke last night.