Crew members of a ship previously detained in Dublin Port for nonpayment of wages have barricaded themselves in the ship and claimed they are owed arrears.
The Russian and Latvian crew of the Latvian-owned, Jamaican-registered vessel, now outside Heysham, England,
have barricaded themselves into a section of the ship along with two ITF inspectors, Ken Fleming and Bill Anderson, because, Mr Fleming said, they "are in fear of our lives".
The International Transport Federation (ITF) is to make an application to the Admiralty Marshall in England to have the Merchant Brilliantarrested.
If that were to happen, the ship would be immobilised in its current position and a skeleton crew left on board until the issue of the arrears is resolved.
Irish and British trade union leaders have condemned events on board the ship.
Siptu president Jack O'Connor and RMT (British National Union of Rail, Maritime and Transport Workers) general secretary Bob Crow have described the situation as a disgrace and further evidence of the race to the bottom that is occurring in sectors of the labour market.
Mr O'Connor said it was "further evidence of the need for proper controls in the maritime industry".
"This confrontation is yet another demonstration of the race to the bottom and of the fact that as long as loopholes exist there will be no shortage of unscrupulous employers ready to exploit them," he added.
Last December, the beneficial owner of the company, ADG Shipping, agreed to pay crew members arrears of €153,000 after the High Court had arrested the ship when the ITF had discovered the arrears.
Following the dispute, the Merchant Brilliant, was switched from the Dublin-Heysham route to Belfast-Heysham.
New discrepancies were uncovered by Mr Fleming in Belfast on Sunday.
Crew members say they are owed $200,000 (€150,000) in arrears, and they only agreed to sail on condition that Mr Fleming accompanied them.
The crew agreed to leave Belfast and sail the vessel to Heysham, under protest, at the request of Norfolk Lines, which had chartered the vessel for its freight service.
However on arrival in Heysham yesterday, Norfolk Lines took the ship off charter, and the harbour master insisted it leave port to make way for other vessels. It left the port at 8pm and has been kept out to sea ever since.
Last November, ADG was forced to pay $167,000 (€127,000) in back wages to crew on another vessel, the Merchant Bravery, to settle a claim of underpayment supported by the ITF. The Merchant Braveryno longer operates in Irish waters