Six men were arrested after trouble broke out on the Stena HSS ferry en route from Belfast to Stranraer in Scotland and erupted again on its return sailing.
RUC officers were waiting when the ferry docked in Belfast at 2.30 a.m. on Saturday. As passengers disembarked fighting broke out in the terminal, with up to 70 people involved.
A number of people were injured and taken to hospital, where fighting again broke out, according to police.