"UNHCR urges on humanitarian grounds that people on board this ship be allowed to disembark as soon as possible, said George Okoth-Obbo, UNHCR Director for Protection.

"At this point in time, the main priority should be to help these people and not let them drift on the high seas in precarious conditions."

The Spanish air rescue service spotted the Marine I on January 30, apparently adrift. A day later a tugboat from the Spanish rescue service approached the ship and has since been accompanying it.

Spain, Mauritania and several countries in west Africa have refused access to the vessel, which is believed to contain people from Africa, Pakistan, India and Bangladesh.

Okoth-Obbo added that measures must be in place to identify people who wish to seek asylum or may be in need of international protection and to channel such claims appropriately.

"This state of affairs can seriously threaten the integrity of the time-honoured humanitarian tradition and legal obligation to assist people in distress at sea," said Okoth-Obbo.