An Australian nurse who has said he was forced by the Islamic State movement to work as a medic in Syria faces prosecution under counterterrorism laws when he returns to Sydney on Friday, police said.

Adam Brookman, 39, could become the first person to be charged under tough new laws which make it a crime to even set foot in the Islamic State stronghold of al-Raqqa province in Syria without good reason.

Brookman was voluntarily returning to Australia with a police escort on a flight from Turkey where he had surrendered to authorities, Australian Federal Police said in a statement.

He was "subject to ongoing investigations" but has not been charged, police said.

"The public can rest assured that any Australian who is identified as a threat to security will be investigated by the relevant agencies," the statement said.

"If there is evidence an Australian has committed a criminal offence under Australia law while involved in the conflict in Syria and Iraq, they will be charged and put before the courts," it said.

Brookman, a Muslim convert and father of five children who live in Melbourne, told Fairfax Media in May that he went to Syria last year to do humanitarian work for civilians caught in the conflict. He said he was innocent of any crime.

Brookman said he was forced to join Islamic State militants after being injured in an airstrike and taken to a hospital controlled by the group.

"After I recovered, they wouldn't let me leave," he told Fairfax.

He won the militants' trust by working as a medic and was able to escape in December to Turkey where he eventually surrendered to authorities.

Brookman told Fairfax that he opposed the violent and extreme actions of Islamic State militants, including the beheading of their captives.

"Of course there will be an investigation. That is fine. Hopefully things don't look that bad," Brookman told Fairfax.

It is not clear whether Brookman was still in Syria on Dec. 4 when Australia made being in al-Raqqa a crime punishable by 10 years in prison. If charged, the onus would be on Brookman to prove he had a legitimate reason to be in the terrorist hotspot.

Australian police issued an arrest warrant in June for Australian doctor Tareq Kamleh who is working in an al-Raqqa hospital and has appeared in an Islamic State movement recruitment video urging Western medical professionals to join him.

Kamleh faces three terrorism offenses carrying a maximum total of 45 years in prison if he returns to Australia.