Leaking oil rig ablaze in Timor sea

Australia promised an investigation today after a massive fire erupted on an oil rig that had been leaking into the Timor Sea - the latest drama in a 10-week saga to plug the hole.

Rig operator PTTEP Australasia said no-one was injured and non-essential workers were evacuated after the fire broke out on the West Atlas rig and Montara wellhead platform yesterday.

The blaze started when workers began pumping heavy mud into a leaking well casing. An estimated 400 barrels of oil a day have escaped from the hole since 21 August.

Officials planned to pour more mud into the leak today, hoping to remove the source of fuel from the fire, which was sending massive plumes of smoke into the sky.

PTTEP Australasia's chief financial officer Jose Martins said the company did not know how the blaze started.

"Presently there are many unanswered questions, including what caused the fire," Mr Martins said in Perth.

"Our sole focus now is the safety of all personnel, bringing the fire under control and completing the well kill."

Federal resources minister Martin Ferguson said once the spill was contained he would launch an official inquiry.

"Our requirement is to assess the cause of the accident and any lessons to be learnt, and that could lead to a change in the regulatory environment," he told Australian Broadcasting Corporation radio.

The oil slick from the rig, about 150 miles off Australia's north-west coast, now stretches across thousands of miles of remote ocean.

Indonesia said last week that thousands of dead fish and clumps of oil had been found drifting near its coastline.