Irish Ferries has cancelled all sailings on the MV Ulysees between Dublin and Holyhead due to “technical reasons.”
The ship has been moved to dry dock in Belfast and the company said it will remain out of service “until repairs can be completed.”
“At this point, it is expected that the ship will return to normal service by the middle of next week,” it said in a statement.
The company said it is in the process of notifying affected passengers and has insisted they will all be accommodated on an alternative ship or sailing.
It is unclear how many passengers will be affected.
Services on the Epsilon between Dublin and Cherbourg next Saturday and Sunday have also been cancelled.
Irish Ferries has apologised to customers for the “unforeseen disruption” and confirmed that sailings of its other ships between Dublin and Holyhead continue to operate.
The difficulties come after the company was forced to cancel thousands of holiday bookings to France this summer because the new WB Yeats ferry is not yet ready for service as promised.
Nearly 20,000 people planning to travel over the summer months were affected.