Australia is to start targeting jihadist support and logistics resources in Iraq and Syria, as it broadens the scope of its air war on the Islamic State group, officials said Thursday.

The staunch US ally has some 780 defence personnel in the Middle East supporting its operation against IS and has been active in Iraq for months.

Many are based in Iraq with 400 attached to the Air Task Group flying six F/A-18 Hornets on bombing missions. Late last year Australia also started carrying out air strikes against IS targets in Syria as part of a 60-nation, US-led coalition.

Chief of defence Air Chief Marshal Mark Binskin said that domestic laws needed to be updated to allow his pilots to attack support and logistics targets, as they were currently limited to "only target those Daesh (IS) forces that are taking a direct and active part in hostilities".

He said the amendments were also necessary to protect defence force personnel at risk of being prosecuted domestically for their actions against IS if courts "take a narrower interpretation of Australia's obligations under international law".

The legal changes would allow the defence force "to target Daesh at its core, joining with our coalition partners to target and kill a broader range of Daesh combatants, which is consistent with international law", Prime Minister Malcolm Turnbull told parliament in Canberra.

He also confirmed his administration would soon put forward legislation, first announced in July, to keep high-risk jihadists in detention beyond the completion of their sentences and to tighten control orders that aim to prevent an attack by limiting a person's movements, communications and activities.

Canberra raised the terror threat alert level to high in September 2014, while parliament has passed new national security laws including cracking down on its nationals travelling to terrorist hot spots without a valid reason.

Sydneysider Hamdi Alqudsi -- believed to be first person charged under one of the new laws, the foreign incursions act -- was Thursday sentenced to a minimum of six years' jail for helping several people go to Syria to fight.

Turnbull added that more than 60 Australians have so far been killed in Iraq and Syria, while some 200 people back home had been investigated for supporting militant groups.

Ten attacks have been foiled on Australian soil since the alert level was raised, he said, but three have taken place, including the murder of a police employee in Sydney in October.