Prime Minister Malcolm Turnbull has cast doubt on whether Syrian leader Bashar al-Assad can be part of a peaceful solution to the six-year civil war.
Mr Turnbull told reporters in Port Moresby, Papua New Guinea, the continued role of Assad must be under enormous question.
"I have grave doubts as to whether he can have any continuing role in the settlement. The crimes he has committed against his own people are so enormous."
Satellite image released of Syrian air-strike target
"His actions, his horrendous, criminal actions, gassing women and children, babies, that surely disqualifies him from a continuing role."
The Assad regime has been blamed for a chemical weapons attack which killed at least 80 Syrian people, many of them women and children.
In response, the US fired 59 Tomahawk missiles at the government-controlled Shayrat base from destroyers in the eastern Mediterranean Sea on Friday.
US strikes Syrian air base
Mr Turnbull said it was now is up to the United Nations Security Council and Russia in particular, to bring this conflict to an end.
"If the great powers engaged in this conflict, the local and regional powers work together, then peace can be found," he said.
The prime minister said he had spoken to Defence Minister Marise Payne as well as the chief of the defence force on Saturday and the situation remained unchanged.
