Australian aircraft are operating over Iraq in non-combat roles in support of the US-led mission to defeat Islamic State.

Two RAAF aircraft have begun missions into Iraq to support US and other coalition combat aircraft taking on Islamic State.

But federal cabinet has yet to get Iraqi government approval for RAAF Super Hornets to undertake bombing raids.

Prime Minister Tony Abbott told parliament on Wednesday while Australia was reluctant to “reach out” for conflicts thousands of miles away the IS, or ISIL, extremist group was reaching out to Australia.

Last month the government pre-deployed eight Super Hornets, a Wedgetail early warning and control aircraft, a refueller aircraft and 600 military personnel including special forces members to Australia’s Middle East base in the United Arab Emirates.

Mr Abbott said while a final decision had not been made to commit the Super Hornets to airstrikes, the Australian Wedgetail and refueller aircraft would start flying over Iraq from Wednesday in support of allied operations.

“Ours are support operations, not strike missions,” he said.

“Australian air strikes await final clearances from the Iraqi government and a further decision by our own.”

Opposition Leader Bill Shorten said Labor supported the action and understood the need to get the legal and diplomatic framework for the mission right.

“In the days ahead our thoughts are with the men and women of the ADF,” he said.

Foreign Minister Julie Bishop said the 310 international coalition air strikes conducted to date in Iraq and Syria were making a difference.

“These air strikes are denying ISIL a safe haven and are degrading its ability to operate with impunity across the region,” she said.

“Decisive international action is essential … and Australia will play its part.”

The government statements to parliament came as US Pentagon spokesman Rear Admiral John Kirby told reporters in Washington that military action alone would not defeat IS.

“No one said this would be easy or quick, and no one should be lulled into a false sense of security by accurate air strikes,” Rear Admiral Kirby said.

“We will not, we cannot bomb them into obscurity.”

Over the past three weeks, Australia has undertaken two humanitarian aid drops and five military stores deliveries into Iraq.