Australia is poised to bar its citizens who have fought for ISIS from returning home for up to two years, under new laws discussed in Parliament on Tuesday.
The controversial legislation would give hardline Home Affairs Minister Peter Dutton the ability to invoke "exclusion orders" to stop suspected terrorists returning to the country.
It is based on similar legislation introduced in the UK, where a judge decides whether to impose an exclusion order.
Mr Dutton told Parliament in early July that the bill targets 230 Australians who travelled to Syria and Iraq to fight for ISIS, 80 of whom were still in active conflict zones.
Concerns have been raised that the Australian proposal could be unconstitutional and places too much power in the minister's hands.
The opposition Labor Party called for it to be referred back to a parliamentary intelligence and security committee for further consideration.
Shadow home affairs minister Kristina Keneally said the opposition would support the bill but wanted a system that was "constitutional, keeps Australians safe and that withstands High Court challenges".
It is one of several controversial measures being considered by Parliament in the first legislative sitting week since Australia's conservative government was re-elected in May.
Other proposals include repealing the "medevac" law, which allows sick asylum seekers and refugees held in Pacific camps to be taken to Australia for medical treatment.
The opposition has appeared reluctant to back a repeal of the law, with Labor leader Anthony Albanese telling Sky News on Tuesday that he did not believe the government had made a case for change.
"There are some 90 people who have been brought to Australia under the Medevac legislation," Mr Albanese said.
"There's 900 who have been brought to Australia by the government itself prior to the medevac legislation being there."
The UnN and human rights groups have roundly condemned Canberra's hardline approach to the nearly 900 refugees who remain on Nauru and Papua New Guinea's Manus Island.
But Australia has defended its policies as humanitarian, saying hundreds of people have drowned at sea trying to reach the country and that it is deterring people from making the journey.
