The European Causeway, which can carry up to 410 passengers, is about five miles off Larne Harbour.
A P&O ferry, which operates between Larne and Cairnryan, is adrift off the coast of Larne.
The European Causeway, which can carry up to 410 passengers, is about five miles off Larne Harbour.
It left Cairnryan at about 12:00 BST and was due to arrive at Larne Harbour at 14:00.
P&O said the incident occurred due to a mechanical issue in the Irish Sea and a full inspection will take place when the ship is back in port.
Tugs from Larne and Belfast have been deployed to guide it back to port, P&O tweeted.
RNLI lifeboat from Larne and Red Bay were launched to the vessel.
It is understood the Queen Victoria cruise ship, en route to Belfast for a refit, is also on site, along with a coastguard helicopter from Prestwick.
Image source, Vesselfinder
Ship tracking websites showed the vessel’s automatic identification system (AIS) status is set to Not Under Command, according to tracking websites Marine Traffic and My Ship Tracking.
That status is reserved for use when a vessel, “through some exceptional circumstance is unable to manoeuvre as required by these rules and is therefore unable to keep out of the way of another vessel”.
P&O has been contacted for comment.
The Rail, Maritime and Transport workers’ Union (RMT) said the reports were “deeply concerning, not least for the agency crew and passengers onboard”.
Due to a mechanical issue with the Causeway in the Irish Sea, tugs from Larne and Belfast were deployed to guide it back to port. Once the ship is back in Port a full inspection will take place
— P&O Ferries (@POferries)
More to follow
