The crew of the ship are refusing to leave Belfast port

Among the complaints of the Filipino crew of the Naxos are claims that the ship leaks in heavy seas.

The Maritime and Coastguard Agency is due to inspect the ship on Wednesday.

Ken Fleming of the Siptu union said the ship would not sail until grievances were addressed and "anyone wishing to be repatriated is allowed to go home".

The ship is owned by Jinyang Shipping in Korea.

Fifteen of its 20 crew members are believed to have stood down.

Mr Fleming, Siptu's international transport federation inspector, claimed there were serious pay arrears for the crew with some being paid 180 US dollars a month for 300 hours work.

"The crew only undertook their first safety drill on their approach to Belfast. They should have had at least four drills since coming on board," Mr Fleming said.

"The crew also swore to me, but I have no way of knowing this for sure until the vessel is inspected, that it is taking in salt water in heavy seas."