Prime Minister Tony Abbott says the Australian Defence Force remains on standby to provide further assistance in Iraq.

Australian defence forces stand ready to provide further assistance in Iraq after a “pause” in the humanitarian mission, Prime Minister Tony Abbott says.

US President Barack Obama says the Mount Sinjar siege by Islamic State militants in northern Iraq has been broken and further humanitarian air drops are unlikely to be needed.

Most of the US military personnel involved in the mission are set to leave Iraq in coming days.

Mr Abbott visited the Joint Operation Command Centre near Canberra on Friday to thank ADF personnel for their efforts in conducting a Hercules air drop of supplies.

While US air strikes had “at least checked the ISIL advance” and the humanitarian mission had been paused, it was important to keep options open should the advance resume.

The prime minister doesn’t envisage the deployment of Australian combat troops, but is continuing to consult with allies about the best way forward.

“Australia certainly stands ready to assist people in trouble wherever we reasonably can,” Mr Abbott told reporters.

He wants Australian operations to be effective in supporting humanitarian ideals “deeply at risk in recent weeks because of the murderous advance of ISIL forces in northern Iraq and elsewhere”.

Mr Abbott has not spoken with President Obama since July 24, but defence and foreign affairs ministers consulted with their American counterparts at the AusMin talks in Sydney on Tuesday.

Opposition Leader Bill Shorten said he had been assured by the government that it had no plans for Australian combat troops to be deployed to Iraq, which doesn’t preclude humanitarian operations.

He welcomed news that Iraqi Prime Minister Nouri al-Maliki would heed calls to step aside, saying his exit would help bring about a more inclusive Iraqi government.

He said Iraq needed to include its Sunni minority along with the Shia majority in the same government, and other groups need to be heard, including the Kurds.

“I think there has been a lot of significant American diplomacy, and Iraqi national political debate, which will see – hopefully – a coalition government formed including all of the views in Iraq,” Mr Shorten told reporters in Melbourne on Friday.

“This, hopefully, will starve the terrorists, fundamentalists and the extremists of oxygen to wreak their particular form of havoc in Iraq.”