If Mobil failed to make a decision by then, the government would force its hand and evict it from the site, SA Treasurer Kevin Foley said yesterday.

But Foley said the government was optimistic that this would be unnecessary and Mobil would reach a decision within weeks.

"I am confident that in the next few weeks the government will reach a position with Mobil that will see the clean-up of the site commence," he said.

Before its closure in 2003, the refinery was producing about 10% of Australia’s transport fuel.

Reopening the facility would help pump more petrol into the Australian market, potentially reducing the soaring cost of petrol caused by record crude oil prices.

The state government and federal government want to see the plant re-opened but Mobil has not decided whether it would be viable in the long term.

But the government was prepared to go to the state election – to be held on March 18 and widely expected to be won by the Labor government – proposing to pass a law to evict Mobil from the site and bill the company for the clean-up.

A clean-up could be very expensive. Asbestos and toxic chemicals have been buried at the site.

Safework SA, the state government body that oversees occupational health and safety, last week launched an investigation into that Mobil covered up oil spills, dumped toxic waste water in the ocean and exposed up to 3000 people to asbestos dust at Port Stanvac.