Aust still in talks over Syria airstrikes

Australia is yet to formally respond to a US request to expand its air operations against Islamic State in Iraq to targets in Syria.

Foreign Minister Julie Bishop says the government is seeking legal advice about the request and is also consulting with other coalition countries, as well as Iran.

"We don't want there to be any misjudgment ... about what we're doing," she told 2GB Radio.

Ms Bishop lamented the destruction of a historical Roman-era temple and antiquities at Palmyra, an ancient oasis city in the Syrian desert northeast of Damascus.

"This is a crime against humanity," she said.

"This strikes at the very heart of who we are as a civilisation."

Ms Bishop previously met with UNESCO director Irina Bokova to discuss ways to stop terrorists from raising money through the blackmarket sale of antiquities.

Extremists were obliterating history in order to impose their sick ideology over the region, she said.