A tanker carrying 20,000 metric tons of liquefied petroleum gas is on fire in Chinese waters east of Hong Kong.

Fire boats sent from Hong Kong and mainland China have been tackling the blaze, which broke out in the engine room early on Sunday.

We are keeping everybody far away from the ship

Hong Kong maritime rescue official

There is a risk of a huge explosion if the fire spreads to the tanks containing the highly inflammable liquid petroleum gas.

Flames are raging in the vessel's superstructure and accommodation areas, and local television showed grey plumes of smoke billowing from the vessel.

"The fire is still on, but luckily in the back part of the ship, away from the cargo area," said Captain Ravi Dewan, head of Hong Kong's Maritime Rescue Co-ordination Centre.

"The head of the ship is into the wind so the wind is pushing the fire to the back rather than towards the cargo area," he told reporters.

He said that if the gas did ignite, there would be a "major, major explosion".

However he believed that, even if the ship did sink, there would be no environmental hazard from the gas, unlike oil.

"There is no pollution risk", he said.

Nuclear plant not at risk

All 34 crew members from the Panamanian-registered Gaz Poem were picked up safely after abandoning the ship.

The ship, bound for the Chinese port of Yan Tien, was 24 miles (40 kms) east of Hong Kong, near Waglan island, when the alarm was raised.

Other maritime traffic is being kept away from the area because of the danger of the gas igniting.

However, Captain Dewan said the Gaz Poem was "very far away" from the Daya Bay nuclear power plant in southern China, or any residential area.

He added that he expected the vessel to carry on burning for hours after raging for more than half a day.

The incident comes less than a week after a Liberian-registered tanker sank off the north-western coast of Spain, spilling thousands of tons of heavy fuel oil.