The video, shown on Australian television after reportedly being aired on Dubai-based Al-Arabiya television, shows the man holding an automatic rifle and warning of attacks while criticising British Prime Minister Tony Blair and US President Geoge W. Bush.

"The honourable sons of Islam will not just let you kill our families in Palestine, Afghanistan, Kashmir and the Balkans, Indonesia, the Caucuses and elsewhere," the militant says in what local media said appeared to be an Australian accent.

"It is time for us to be equals. As you kill us, you'll be killed. As you bomb us, you will be bombed."

The masked man, wearing a black balaclava and combat gear, claims a group of Al Qaeda "fighters" carried out an attack on a helicopter that killed 16 soldiers in Afghanistan in June.

The video features blurred footage said to be of a rocket attack on the helicopter.

A spokeswoman for the attorney-general's office said the Australian Security Intelligence Organisation was "looking at the footage very carefully".

The Australian government is debating tougher security laws and action against anyone encouraging militancy amid fears that Australia could be the target of attacks similar to those that killed more than 50 people in London last month.

Australia contributed troops to the US-led invasions of both Afghanistan and Iraq.