The fire was still raging on the New Diamond tanker carrying about 2 million barrels of oil, said the spokesman, Captain Indika de Silva.

There were 23 crew on board, one of whom is presumed dead. The rest have been taken off the ship by the Sri Lankan navy, with one injured crew member flown to the capital Colombo for treatment.

There were no signs of an oil leak from the vessel, de Silva added. Ships from the Russian navy and the Indian coastguard have been assisting in the firefighting.

The fire that broke out in the engine room of the New Diamond on Thursday morning had spread to the bridge of the ship, chartered by Indian Oil Corp (IOC), though it has yet to reach the cargo area, the Sri Lankan navy said.

Initially, the ship was stranded 38km east of the Sri Lankan town of Thirukovil, but drifted within 25km of the coast after being abandoned. Authorities were now towing it eastward, away from the coast, de Silva said.

"The missing Filipino sailor is presumed dead. He was badly injured when a boiler exploded," de Silva told Reuters, citing crew who were rescued.

"There were five Greek and 18 Philippine nationals among the crew. One of them was injured and he was airlifted out of the ship and the rest were accounted for."

While there are no signs of a leak, Sri Lanka's meteorology department has already modelled the impact of 70,000 tonnes of crude oil - a quarter of the ship's cargo - spilling into the ocean.

Dharshani Lahandapura, chair of Sri Lanka's federal Marine Environment Protection Authority, told Reuters that any spill from the ship would be catastrophic for marine life.

Australian Associated Press