Australia is in discussions with the US about possible participation in humanitarian airdrops over northern Iraq, Prime Minister Tony Abbott says.

“We’ve been asked to consider participation in humanitarian airdrops,” Mr Abbott told reporters in Sydney.

“This is a potential humanitarian disaster,” he said of the situation in northern Iraq, where tens of thousands of mainly women and children were surrounded by Islamic State militants who were threatening to kill them.

It comes as US aircraft launched attacks on targets of militants in northern Iraq.

Two C-130 Hercules aircraft based in the United Arab Emirates could possibly be used to assist in drops of food, water and other humanitarian supplies on Mount Sinjar, where 40,000 Iraqis are trapped.

Australia will be ready to assist within days should it be called to action.

“We are looking to assist as quickly as we can,” Mr Abbott said.

The prime minister said it was important Australia join international partners on helping stifle a potentially large-scale humanitarian disaster.

He warned of the “medieval barbarism” of the terrorist group Islamic State, formerly known as ISIL or ISIS in its efforts to set up a “terrorist state”.

“This is designed to protect civilians from a murderous onslaught,” Mr Abbott said.

Mr Abbott also dismissed reports Australian warships could be used to allow American commanders to launch missile strikes.

“There’s been no discussions along those lines whatsoever.”