Prime Minister Tony Abbott has announced Australian aircraft from today will start flying over Iraq in support of allied operations.

Mr Abbott said the federal cabinet had not yet approved combat flights, but early warning and control aircraft and refuellers were being deployed into Iraq.

“Australian airstrikes await final clearances from the Iraqi government and further decision from our own,” he told parliament.

Mr Abbott said it was in support of United States and other coalition aircraft.

“Because ISIL has global ambitions, international security and national security are indivisible,” he said.

"As always, the Australian government will do whatever is possible to keep our people safe."

Opposition leader Bill Shorten offered conditional support for the plan.

He remarked on the “bravery, professionalism and skill for the men and women of our defence force and the resilience of their families”.