SYDNEY: An oil rig which has been leaking thousands of barrels of oil into the Timor Sea off Australia's northwest coast for more than two months was on fire Sunday, the company said.

"PTTEP Australasia reports the West Atlas rig and Montara well head platform are on fire," the firm said in a statement.

A spokeswoman for the company said specialists had finally succeeded in the first stage of plugging the well, which has been spilling up to 400 barrels of oil each day into the ocean since August 21.

"They had not actually stopped or killed the leak... and then unfortunately the fire broke out," she told AFP.

PTTEP said all personnel working at the isolated site some 250 kilometres (155 miles) offshore had been reported safe and non-essential staff were being evacuated. The company gave no indication of the severity of the blaze.

The rig's operators have been struggling for weeks to stop the leak, which environmentalists fear poses long-term risks to the area's wildlife.

On Friday, a biologist commissioned to carry out an Australian government survey of the West Atlas drilling rig found that the massive spill posed an immediate risk to dozens of marine species.

"It is possible that species that are dying or dead and lying in oil-affected water may not stay afloat for long periods of time, making it unlikely that we would find large numbers of dead animals," James Watson wrote.