Prime Minister Malcolm Turnbull says the Syrian government's use of chemical weapons in an attack on the rebel-held town of Khan Sheikhoun had to be punished.
"The use of these weapons, under any circumstance, is illegal and abhorrent. It's a violation of international law. It is a war crime."
United States president Donald Trump's defence secretary phoned Australia's defence minister, Marise Payne, this morning to let her know the strike was coming.
Australia did not participate in the execution, but Mr Turnbull says the United States has his full support.
"Australia was not involved in the strike, but we remain fully committed as a coalition partner to our ongoing military operations in Iraq and Syria."
Nonetheless, the Prime Minister says Australia is not at war with Syria.
"We are not at war with the Assad regime, and the United States has made it clear that they are not seeking to overthrow the Assad regime."
As is usual with military operations, Labor has offered bipartisan support.
Opposition Leader Bill Shorten says Mr Assad's allies, Russia and Iran, should join in the condemnation.
"You can't gas the citizens of your own country. That's a war crime, pure and simple. And I think it's time for (Vladimir) Putin and the Russians to step up."
Malcolm Turnbull has called on the United Nations to find a solution as soon as possible.
Ceasefire talks between the Syrian government and opposition forces have repeatedly broken down.
A Middle East analyst at the Australian National University, Professor Amin Saikal, says further US attacks may be needed to force Mr Assad to the negotiating table.
"If the Americans follow their cruise missile attacks with further operations against the Assad regime's targets, then I think that that may well really bring it home to the Assad regime, as well as to the Russians, that the only way out of this conflict is a political settlement."
