Prime Minister Kevin Rudd has condemned snipers trying to disrupt the work of UN chemical weapons inspectors in Syria.
Snipers have shot at United Nations experts as they sought to investigate last week's deadly chemical weapon attack near Damascus.
The lead vehicle in a convoy was hit "multiple times" by gunfire as the inspectors tried to reach Ghouta, east of the Syrian capital.
Mr Rudd said the United Nations Security Council would be discussing its response.
"I'm deeply disturbed today to have received reports that the first group of UN chemical weapons inspectors' motor vehicle was fired upon by unidentified snipers," Mr Rudd told ABC Radio.
"We need a strong possible menu of response options."
Mr Rudd warned against rushing to immediate judgement.
Australia will take over the presidency of the UNSC on Sunday.
Hundreds of people were killed in an attack last week at Ghouta in which chemical weapons are believed to have been used.
Western nations have blamed President Bashar al-Assad's forces for the attack.
But the Syrian government has blamed opposition rebels.
"Under international law this is a grave breach of not just human rights, it's a humanitarian assault," Mr Rudd said.
"Potentially it's also a crime against humanity."