The Swansea/Cork Ferries vessel the MV City of Corkis thought unlikely to sail before next Tuesday, after it failed a safety test last night.
The Department of Marine will meet senior officials from the company next Tuesday and has warned that if safety procedures aboard the ship do not improve, the vessel may be suspended from service indefinitely.
The car ferry is tied up in Wales after British inspectors refused to allow it sail because it was not satisfied with crew safety drills.
The ship has been the subject of a number of inspections since it failed a similar test in March. "A lack of preparedness as demonstrated by fire drills, full muster, abandon ship and damage control drills" was cited by the British Maritime and Coastguard Agency as the reason for its detention.
The Greek-owned, Portuguese-registered vessel is leased to Swansea/Cork Ferries and is manned by a mainly Greek crew.
The company has apologised to passengers inconvenienced by the cancellation of the ferry which sails to Swansea five times a week.