Victoria is considering tougher laws to crack down on eco-terrorist attacks on power stations after a threat to a Melbourne power company executive by an extremist US group.
The FBI has described the group as America's top domestic terrorist threat.
The hardline hand-delivered a menacing letter to the eastern suburbs home of Graeme York, head of the Hazelwood power plant in Gippsland.
In it, the group told Mr York he was responsible for the dirtiest power station in Australia, and the most polluting in the industrialised world.
"We hold you personally accountable for this assault against our Earth," the letter said. "We do not take lightly to the perpetual destruction of our land-base for the selfish and short-term objective of fattening your bank account.
"The irreplaceable and precious eco-systems of this Earth are worth much more than your manicured lawn, expensive car, and opulent suburban house. Your property will not remain safe so long as Hazelwood continues to pollute at such an inexcusable level."
A spokesman for the North American ELF press office Jason Crawford said ELF targets did not usually receive warnings of "economic sabotage" actions.
"I think he (Mr York) should consider himself lucky, that a lot of ELF actions aren't predicated by a letter delivered to them."
Mr York would not comment yesterday, and a plant spokesman said only that the matter had been referred to police.
Police have confirmed they are investigating the threat.
The threat against Mr York is the latest in a long line of attacks on Victorian power plants.
Last month, seven Greenpeace members were arrested after chaining themselves to a coal digger at Hazelwood, and in September, activists from the Real Action on Climate Change protest group shut down power generation at the Loy Yang power station for five hours.
More than 150 people have been arrested in Australia in the past year for disrupting power and coal plants.
In Victoria, offences of damaging property, threatening to sabotage, and sabotage, carry maximum prison sentences of between 10 and 25 years imprisonment.
But state Attorney-General Rob Hulls said the Government was re-examining those laws to see if the legislation was sufficient.
"One option being looked at is the ability to prosecute action that does not involve actual damage to property but causes major disruption or cost to the community."
He said physical threats to a person were covered by penalties under the Crimes Act.
The Earth Liberation Front says "direct action" - vandalism or arson - is needed to stop environmentally harmful acts.
The FBI says the group is responsible for more than 1200 acts of terrorism in the US, causing more than $US100 million ($A125 million) damage. The acts have included fire-bombing housing developments, torching car yards and attacking forestry research centres.
Earth Liberation Front is not a proscribed terrorist organisation in Australia, and a spokesman for federal Attorney-General Robert McClelland declined to comment on whether outlawing the group would be considered.
