Australians should be prepared for more small-scale and "lone wolf" attacks as the threat of terrorism evolves, Attorney-General George Brandis has said in an address to the first international forum on countering improvised explosive devices (IEDs).

The forum aims to boost collaboration between police and government officials in preventing IED attacks, and comes just weeks after an explosion at a Bangkok shrine involving an IED killed 20 people.

Mr Brandis said societies now "live in an age more dangerous than we had ever imagined before... where extremist groups operate without regard for national boundaries and have a footprint in most countries, including our own".

"It is an age when all you need to commit an act of terror is a knife, a mobile phone and a victim," he told more than 300 delegates from 70 nations at the Canberra conference, organised by Interpol and Australia's federal police and defence agencies.

The nation's first law officer said the conflict in Syria and the activities of jihadist groups such as Islamic State showed the changing nature of terrorism and a shift in tactics, from large-scale September 11-style attacks to smaller, "lone wolf" plots.

"As well as our efforts to stem the exodus of would-be foreign fighters (to the Middle East), we should be prepared for more of these types of attacks in Australia," he said.

The Australian government has raised its terror threat level to high, introduced new national security laws and conducted several counter-terrorism raids to address the concerns.

The government says some 120 Australians have left to fight in Iraq or Syria with 160 actively supporting extremist organisations at home through financing and recruitment.

Interpol said Wednesday that urgent action was needed as the threat of terrorism had reached "unprecedented heights".

The Internet has helped facilitate knowledge on how to build IEDs beyond war zones, the global law-enforcement body added, estimating that some 10,000 civilian casualties have resulted from IED attacks since the start of this year -- almost half stemming from suicide attacks.