US Admiral Sam Locklear with Tony Abbott at the USS Arizona Memorial in Pearl Harbour in Hawaii on Saturday. He arrives back in Canberra on Monday.

US Admiral Sam Locklear with Tony Abbott at the USS Arizona Memorial in Pearl Harbour in Hawaii on Saturday. Photo: Andrew Meares

Foreign Minister Julie Bishop says she does not expect Australian troops to return to Iraq to battle a jihadist insurgency which has seized control of a vast swathe of territory in the north of the country.

Ms Bishop said while Australia was yet to receive any request for assistance from the Iraqi government, it stood ready to provide support to alleviate what she described as an ''humanitarian crisis.''

Hundreds of people have been killed and half a million people displaced by the offensive by the Islamic State of Iraq and the Levant, which last week gained control of Iraq's second-largest city, Mosul.

The Department of Foreign Affairs urged Australians in Iraq to leave the country by commercial flights from Baghdad if it was safe to do so, warning its ability to provide consular assistance to any Australians who remained in Iraq would be limited.

Ms Bishop was a member of the Howard government, which in 2003 committed Australian forces to the US-led invasion of Iraq that toppled the regime of Saddam Hussein.

Asked on Sunday whether this had been a mistake in light of current events, Ms Bishop told Channel Ten: ''Well, I supported the liberation of Iraq at that time. I thought Saddam Hussein was one of the worst dictators on the planet at that time. And his removal was a good thing.''

Another supporter of the 2003 invasion, former British prime minister Tony Blair, hit out critics for linking those events to the current violence. In an article published on his website, Mr Blair blamed the violence on the sectarianism of Iraqi Prime Minister Nouri al-Maliki's government, and the west's failure to act in Syria.

''It is a bizarre reading of the cauldron that is the Middle East today, to claim that but for the removal of Saddam, we would not have a crisis,'' he wrote.

US President Barack Obama has said Washington would not be sending troops but his national security team was preparing a range of other options, likely to include air strikes, to support the Iraqi government.

In Houston on Saturday, Mr Abbott said he would wait to see how the US responded before developing an Australian position. ''The important thing at the moment is to let the Americans work their way forward,'' he said.

On his way back to Australia, Mr Abbott stopped in Hawaii, where he visited a memorial to US sailors killed in the 1941 Japanese bombing of Pearl Harbour. He will arrive back in Canberra on Monday and face question time in the afternoon.

Opposition Leader Bill Shorten said on Friday that any Australian military response would have to be in ''the Australian national interest'' to win Labor's support.

with AAP