The father-of-five spent nearly six years behind bars before last month pleading guilty to performing acts in support or promotion of the commission of an offence under foreign incursion laws.

Brookman, now in his 40s, went to Syria in 2014, telling police he intended to use his healthcare experience to help the local Muslim community.

He trained first as a nurse and later worked as a paramedic for Ambulance Victoria and in hospitals.

Australian authorities first became aware of Brookman's activities in Syria - which included providing medical supplies and performing reconnaissance for Chechen fighters - through a phone call his brother made to the national security hotline about photos that appeared to show him in a war zone.

Prosecutors say Brookman was initially providing medical services in the Aleppo area and later joined a Chechen group in Latakia.

He performed guard duty and weapon maintenance while also providing medical services before travelling on a reconnaissance mission with them in July 2014, prosecutor Nicholas Robinson QC said.

Brookman posted photos of weapons on social media. One showed a cat alongside a pistol and two hand grenades.

"And what is a mujahid without his cat? This one comes fully prepared for any eventuality," he wrote.

He described driving at night without lights down a road "like Swiss cheese" while being shot at by fighter jets, saying his faith had never felt so high and he had never felt so good.

Brookman's barrister Peter Morrissey SC said while supporting foreign fighters was against the law in Australia, Brookman's activities were very different to someone supporting a terror organisation.

He said Brookman's offending was tempered by the fact the Chechen group was fighting against Syria's "barbaric" Assad dictatorship.

"If the Chechens were seeking to resist Hezbollah taking over a town and punishing its inhabitants, that's different to him going somewhere with ISIS to massacre the entire population," he said.

"You could do much worse than what he is proven to have done."

Brookman left Syria in mid-2015, using smugglers to travel to Turkey where he contacted Australian authorities and negotiated his arrest on his return to Australia.

He has been in custody since his return to Melbourne in July 2015.

His lawyers are hoping for Brookman's immediate release after sentencing, and say he hopes to return to his healthcare career on his release, subject to character tests and risk assessments.

"That's what he wants to do, that's how he likes to serve, that's who he wants to be as a person," Mr Morrissey said.

Justice Jane Dixon will hand down her sentence at a later date.

Australian Associated Press