Prime Minister Kevin Rudd says the United Nations has Australia's support for an immediate investigation into the use of chemical weapons in Syria.
During a phone call to UN Secretary-General Ban Ki-moon on Friday Mr Rudd expressed Australia's grave concern about the deteriorating situation in Syria.
They also discussed what next steps the international community should consider.
The world is calling for answers amid claims Bashar al-Assad's regime used chemical weapons to massacre up to 1300 people on the outskirts of Damascus this week.
UN weapons inspectors are in Syria but have not been given permission to investigate the latest claim.
Mr Rudd offered the UN chief Australia's support for an immediate and thorough investigation.
"Australia calls on the Syrian government to respond positively to the Secretary-General's call for co-operation and that it provide full and unfettered access to UN inspectors currently in Damascus," he said in a statement on Friday.
He said the events were "a tragedy of unspeakable proportions".
Asked earlier whether Australia would consider committing troops to a possible international intervention in Syria, the prime minister said he is taking a "calm and measured approach".
"I take this step-by-step. I'm not in the business of making chest-beating announcements," he said.
