Latest Australian ISIL recruit identified as a baby-faced maths whiz from Melbourne

The latest Australian to take up arms with ISIL has been revealed as an 18-year-old teenage boy from Craigieburn, in Melbourne's north.

Described as extremely shy but exceptionally bright, Jake Bilardi has been photographed clutching an assault rifle while sitting between two bearded ISIL soldiers in Syria.

Prime Minister Tony Abbott said the government is doing "everything we humanly can to stop Australians from leaving to go overseas to fight with the death cult".

Midway through last year, Mr Bilardi bought a one-way ticket to Istanbul. Two months later he contacted his family to tell them he was in Iraq training for a martyrdom mission with a suicide vest.

Later he contacted them to say he was too scared to go through with it and preferred to be a soldier in Syria.

At the age of 16, a school friend introduced Mr Bilardi to Islam and he began praying and attending lectures at mosques in Melbourne's northern suburbs.

Later, he connected with an ISIL recruiter online.

Using his alias, Mr Bilardi has tweeted "I'm from Australia ... but I'm a proud traitor" and "9/11 is child's play compared to what's in store for you dogs".

On a blog in his real name, he calls Israel "brutal sadistic murderers" and labels Americans "sick twisted mental patients".

"Somebody's looking out for tell-tale signs of a curious young mind who might be a candidate, and they're going after them in a predatory fashion," terrorism expert Greg Barton said.

The Australian Federal Police said it is aware of Mr Bilardi but will not comment on the case.