PM 'wait and see' on Sharrouf kids' return

Prime Minister Malcolm Turnbull is adopting a wait-and-see approach to the possible return to Australia of the five orphaned children of Islamic State fighter Khaled Sharrouf.

"As soon as we are aware of where they are, what the situation is, we can then make an assessment," he told the Nine Network on Wednesday.

Australians were filled with compassion for the plight of the children, but the government had to put the security of the nation first, he said.

The children's grandmother Karen Nettleton and solicitor Robert van Aalt are believed to have left Australia headed to the Islamic State stronghold of Raqqa, where the children are said to be living.

Ms Nettleton's daughter, Tara, and the couple's children moved to Syria to fight with the terrorist group.

"We understand the human dimension here very keenly," Mr Turnbull said.

He emphasised the grandmother should not be travelling to Syria because it was breaking the law.