His comments came as the Chief of the Defence Force, Mark Binskin, expressed optimism about the coalition campaign in Iraq against the Islamic State, also known as ISIL, after meeting top international military leaders outside Washington, including US President Barack Obama.

Islamic State fighters, meanwhile, consolidated their hold on Anbar province to the west of Baghdad and edged closer to the Iraqi capital.

The Prime Minister said pointedly on Wednesday he had made it clear some time ago to Iraqi leader Haider al-Abadi at a United Nations meeting that Australian commandos were ready to help the nation's beleaguered military in its fight against the Islamic State.

"But we owe it to our special forces only to deploy them with the right legal protections. With the new government of Iraq still forming, it is taking a little longer than we would have liked to put those legal protections in place but I'm confident that the situation will be resolved in the next few days."

Coming closer than he has before to hinting at irritation over the delay with Baghdad, Mr Abbott said it was "only right and proper when we're there to help the people of Iraq, to help the government of Iraq" that Australia be given the same legal protections as those given by Baghdad to American military advisers.

Air Chief Marshal Binskin, after the high-level meeting at Andrews Air Force Base, said the coalition of more than 60 countries had the necessary resolve to "neutralise the ISIL threat".

"Although ISIL has some tactical influence, the coalition has the strategic momentum and partner nations will continue to build on the coalition's successes," he said.

However the complexity and fragility of the coalition was underscored by the recent actions of Turkey - which attended the US meeting. Turkey this week resumed attacks on Kurdish militants within its own borders even while other Kurdish fighters were battling to save the northern Syrian town of Kobane just over the border, and surprised Washington by denying reports it would open a major base to US and other coalition aircraft.

Fairfax Media understands the Iraq government is still keen to have Australian special forces advisers on the ground. But Canberra needs a legal framework, including a "status of forces" agreement, with Baghdad to give the commandos legal immunity if, for instance, they are involved in the death of civilians.

Progress has been slowed by the Eid Muslim holiday, the fact that Iraq's new government still has not chosen a defence minister, and by Baghdad's need to tread carefully around the domestic political sensitivities of giving foreign soldiers legal immunity, it is understood.

Australian commandos will help Iraq's elite special forces in what Defence is calling an "advise and assist" role. With air strikes aiming to contain Islamic State forces in towns and cities, it will then be up to Iraqi and Kurdish ground forces to clean out the militants, widely expected to be a long and very difficult job.