"It will be some weeks away at least," said Esso spokesman Ron Webb told reporters. An explosion at Esso Australia's onshore gas plant last Friday forced the company to shut down all production of crude oil and natural gas in the Bass Strait, a joint venture between Esso and The Broken Hill Pty Co Ltd.

The plant at the complex which was damaged in the fires housed the control room for the crude oil treatment plant and also shared some piping facilities.

Webb said the company was still investigating what needed to be done to bypass the damaged plant and restart crude oil production.

The company said earlier that its top priority was the restoration of gas supplies to the state of Victoria which has had virtually no gas since last Friday.