Aust politicians condemn Syria attack

Australia will consider further sanctions on Syria's Assad regime if it's found responsible for a chemical weapons attack that has killed dozens of people.

"If the Assad regime has used chemical weapons, as is being alleged, that constitutes a war crime, it constitutes a shocking war crime," Prime Minister Malcolm Turnbull told Tasmanian radio station 7AD on Wednesday.

The attack in an opposition-held town in northern Syria has killed dozens of people, leaving residents gasping for breath and convulsing in the streets and overcrowded hospitals.

The Trump administration has blamed the Syrian government for the attack, one of the deadliest in years.

Mr Turnbull condemned the incident as a horrendous attack.

He expected there would be a full investigation, noting Australia had co-sponsored United Nations resolutions about the importance of collecting evidence on crimes of this kind in Syria.

There are already sanctions in place against the Syrian regime.

"We'll be talking with our allies in this conflict to determine what the next step of response and sanctions can be," Mr Turnbull said.

Labor leader Bill Shorten and foreign affairs spokeswoman Penny Wong said the "barbaric and criminal act" highlighted the brutality of the Assad regime towards its own people.

"Chemical weapons are forbidden by the UN and those responsible for this despicable act should be held to account," they said in a joint statement.

They strongly supported the decision to call an urgent meeting of the UN Security Council to respond to the attack, and said the incident confirmed the Assad regime should have no place in a stable, post-war Syria.

Greens leader Richard Di Natale tweeted the scenes from Syria were appalling and "these attacks must be internationally condemned without reservation".