Published Friday, 21 January 2011
Coastguards said it did not appear that the man had gone overboard, though rescuers have not been able to confirm one way or another.
The operation began on Friday morning when the passenger failed to disembark in Scotland, where the ship docked.
Clyde Coastguard in Scotland received a call for assistance at 10am after the person was reported missing from the P&O European Highlander ferry.
It is believed around 30 rescue personnel were involved in the search operation, including the Royal Navy rescue helicopter based in Prestwick, Stranraer and Portpatrick lifeboats and the coastguard in Belfast.
A statement from P&O Ferries said: "We can confirm that a passenger who was part of a coach party that boarded the 7.30am sailing from Larne to Cairnryan, on the European Highlander ferry, was reported missing on arrival in Cairnryan.
"P&O Ferries has conducted a search of the ship and is assisting authorities with their investigations as to the whereabouts of the passenger, including whether the person may have left the ship in a different vehicle."
The statement said as a standard procedure P&O Ferries also alerted the Maritime and Coastguard Agency.
A spokesperson for Dumfries and Galloway Constabulary said: "Potentially we have one person missing from a coach and we are currently making enquiries with the local Coastguard to ascertain the circumstances surrounding it."