Sixteen Australian women and 42 children have been held in the al-Roj camp since the fall of Islamic State after travelling to Syria with their partners, who were members of the terrorist group.

Australian Federal Police Commissioner Reece Kershaw confirmed the force was investigating whether the repatriated Australians had broken any laws.

Under Australian law it is a crime to travel to select war zones, including Syria.

"We have active investigations right now on these matters," Mr Kershaw told a Senate estimates hearing on Tuesday.

"Some of these may or may not be charged."

He said the 17 returned women and children, who have settled in Victoria and NSW, had co-operated with police.

The government says surveillances and restrictions will help mitigate any potential threat of extremism from the returned women and children.

The opposition has attacked the repatriation, saying it brings an undue terror risk to the public.

Opposition home affairs spokeswoman Karen Andrews said the repatriated women being under police surveillance wasn't enough.

"I firmly believe that there was firstly no need for the government to repatriate these women at this point in time," she told Triple M radio.

"There is a risk. There's no such thing as low risk equalling no risk."

Mr Kershaw said federal police were well placed to respond to any extremist threats.

"Have confidence in the well-established framework that enables the AFP to respond and manage extremist threats in Australia," he said.

Federal police will work with the community to support the returned women and children.

Australian Associated Press