Canberra, May 19 (IANS): A suspected Australian Islamic State (IS) terror group fighter is negotiating with authorities over his return to the country, media reported on Tuesday.

It comes amid a warning from Prime Minister Tony Abbott over the possible fate awaiting any Australian who returns home from the conflict, ABC reported.

"If you go abroad to kill innocent people in the name of misguided fundamentalism and extremism, if you go abroad to become an Islamist killer well, we're hardly going to welcome you back into this country," he said.

"The Australian people expect their country to be safe and someone who has been a terrorist abroad could very easily become a terrorist here in Australia."

Lawyer Rob Stary is representing a Victorian man who had his passport cancelled after working in parts of Syria that were controlled by the terror groups Nusra Front and Free Syrian Army, a group of rebels fighting against the regime of Syrian president Bashar al-Assad.

Stary said that talks with the Australian Federal Police (AFP) on his client's return had stalled after weeks of negotiations.

He said despite his client's background as a medic in the conflict, he expected he would face charges.