At least 20 Australians killed in Syria and Iraq fighting for terrorist groups, Brandis says

Attorney-General George Brandis says at least 20 Australians have been killed fighting alongside terrorist groups in Syria and Iraq, and warns that the Islamic State group is using Australians on the frontline as "cannon fodder, bombers and propaganda tools".

Senator Brandis said the number of Australians killed had risen in recent weeks and that Western recruits were being duped into thinking they were an important part of a religious crusade.

Around 70 Australians were still believed to be fighting in the Middle East while another 20 had returned home.

Victoria Police Chief Commissioner Ken Lay said would-be jihadists were "very likely" to be killed if they joined the conflict.

"You'd hope that mainly young men who are considering this understand that they're very likely to get killed if they do go over and fight," he told Fairfax Radio.

"I think it is a very important part of the message about discouraging young men going over to fight."

Mr Lay said police were concerned social media was being used to recruit young people to join the conflict

"Obviously there's attempts to get young people to go over to the Middle East and fight," he said.

"We're still watching it very closely and we're working with other police jurisdictions and other agencies to try and prevent that happening."

Among those fighting is Sydney man Mohammad Ali Baryalei, who has been accused of masterminding a plot to kill random members of the public in Sydney and Brisbane, and had recruited dozens of Australians to fight with extremist groups in Iraq and Syria.

There were reports that he had been killed in Syria, but Vice Admiral David Johnston last month said the Australian Defence Force believed it was less than likely that he was dead.

The Government recently introduced a raft of legislation aimed at stopping would-be jihadists from travelling to the Middle East.

The Foreign Fighters Bill passed Parliament in October, making it illegal to travel to areas declared as terrorist zones without a specific humanitarian or family purpose.

Australians found to be illegally visiting the region could face up to 10 years in prison.

Foreign Minister Julie Bishop used provisions under the bill to declare it an offence for Australians to visit the Al-Raqqa province in Syria without a legitimate reason.

Ms Bishop said the province was Islamic State's de facto capital and said the terrorist organisation directed many of its operations from the banned region.

"I have today declared Al-Raqqa province an area where a listed terrorist organisation is engaging in hostile activity," Ms Bishop told Question Time last week.

"This now makes it an offence under Australian law to enter or remain in the province of Al-Raqqa without a legitimate reason."

The declaration was the first time the new provision has been used to stop foreign fighters travelling to the Middle East to join the terrorist group.