A Greek-owned freighter caught fire in the Caribbean off Venezuela's coast on Christmas Day, killing nine crew members and injuring five others, Venezuelan authorities said.

The Aegean Wind was carrying more than 37,000 tonnes of iron ore from Brazil to Houston, Texas, when a blaze broke out in the mess hall before dawn local time, according to the vessel's owner, Piraeus-based Atlantic Bulk Carrier Management.

The ship was about 100 miles north of Venezuela at the time, and about 34 miles from Margarita Island.

Venezuelan Admiral Carlos Maximo Aniasi Turchio said nine crew members were dead. Six were from the Philippines and the other three were from Greece, he said.

"We don't know if they died from asphyxiation or burns, but the (ship's) commander has confirmed to us that they did die," Aniasi Turchio told Venezuelan state television.

He said five injured crew members were taken by helicopter to Margarita Island and would be transferred later to a military hospital in the capital Caracas.

One was in a "delicate condition" from severe burns, Admiral Turchio said.