(AFP) Nine workers suffocated today when fire possibly triggered by a gas pocket broke out on a supertanker which they were repairing in a Malaysian shipyard, police and a company executive said.

The tragedy happened a day before the Hong Kong-owned "New Renown" was due to leave the yard at Pasir Gudang in the southern state of Johor after a stay of one month.

The eight Malaysians and one Indonesian, aged betwen 18 and 39, were doing welding work inside one of 20 tanks aboard the ship when they were trapped by a flash fire.

"They were trapped and could not find their way out of the smoke-filled ship's hull..." local police chief Superintendent Idris Ismail was quoted by Bernama news agency as saying.

Gas pocket

The men were engaged by Malaysia Shipyard and Engineering (MSE) to instal a new piping system in one of 20 tanks on the 240,830-deadweight-tonne vessel.

MSE chief executive officer Abdul Rahim Abdul Rahman said the bodies were found on one of the work platforms leading to the tank's hatch. He said there was no explosion.

Abdul Rahim, quoted by Bernama , said the blaze could have been caused by a gas pocket emitted by the previous cargo of crude oil.

He said the welding work was being done with electrical equipment but declined to say whether it could have produced sparks.

"The one month that the ship has been here, it has been fully ventilated (of any gas) and other work has been going on well without any such incident...that is why we want to know how there can be gas inside," the chief executive said.

The bodies have been taken to hospital for post-mortems and police have started an investigation.

Noorazam Khamis, a Johor fire officer, said 37 firemen took 10 minutes to control the blaze and prevent it spreading to other sections of the empty vessel.