Turnbull backs US strikes on Syria

Prime Minister Malcolm Turnbull says a US missile strike on a Syrian air base was a swift response to a shocking war crime.

"The Australian government strongly supports the swift and just response of the United States," he told reporters in Sydney on Friday.

"This was a calibrated, proportionate and targeted response."

Mr Turnbull said the US had advised Australia before the missile strike via a phone call between the United States Secretary of Defence Jim Mattis and Defence Minister Marise Payne.

He said Australia was not involved in the strike, but remained fully committed as a coalition partner to "ongoing military operations in Iraq and Syria".

"We have been consistent in our condemnation of the use of chemical weapons in Syria and elsewhere.

"The use of these weapons, under any circumstance, is illegal and abhorrent. It is a violation of international law. It is a war crime. It is a blatant contravention of basic principles of humanity."

Senator Payne confirmed she spoke Mr Mattis on Friday morning.

She said Australia's air task force was confined to operations in eastern Syria including Raqqa, targeting Islamic State militants.

"Australia has also taken appropriate measures in light of this operation to review our force protection arrangements in the middle east," she said.

Mr Turnbull said Australia was not at war with the Assad regime.

"The United States have made it clear that they are not seeking to overthrow the Assad regime," he said.

However, Mr Turnbull said the events of the past few days raised "very real questions" about the role of Assad in any political solution or settlement in Syria.

He said the US had not asked for extra military support from Australia.

Asked about Russia's role, the prime minister said it had a "real responsibility" to ensure the Assad regime complied with international law.

"The fact is there is a solemn obligation on Russia, too, to play its part in bringing this conflict to an end."