A spokeswoman for the attorney-general's office said the government was aware of the US report that a detained senior al-Qaeda leader had told investigators had had drawn up plans to set devastating wildfires in the US.

"Australian security authorities are aware of reports that al-Qaeda has considered starting bushfires in the US as a form of terrorist attack," she said.

"Arson attacks are just one of a wide range of scenarios which have been considered as part of our investigations into al-Qaeda's ability to conduct attacks in Australia," she said.

She did not elaborate on the US reports, but the Australian Associated Press said her comments followed the publication of a leaked US Federal Bureau of Investigation memo about the al-Qaeda detainee's plans.

"The detainee believed that significant damage to the US economy would result and once it was realised that the fires were terrorist acts, US citizens would put pressure on the US government to change its policies," said the memo as reported in the Arizona Republic newspaper.

It said the detainee told investigators his plan called for three or four operatives to travel to the US and set timed explosive devices in forests and grasslands to create several catastrophic wildfires.

Such an attack could have a devastating impact in the tinder-dry conditions of southeastern Australia, which is suffering its worst drought in decades.

At the height of the southern summer in December and January, bushfires destroyed nearly 500 homes and killed for people in the capital Canberra and ravaged large areas around the country's biggest city, Sydney.

The Australian official said the government had received no information about a specific bushfire terrorist threat in the country and had not raised its already high level of terror alert.

"Australian security measures were increased following the September 11 and Bali terrorist incidents and remain appropriate to the assessed level of threat," she said.

"Australia has sound emergency management/services capacity to respond to and recover from any event whether it be naturally, technologically or human caused."

TERRA.WIRE