US Secretary of State John Kerry on Tuesday urged Iraqi prime minister-designate Haidar al-Abadi quickly to form an inclusive government, while ruling out sending US combat troops to the country.

"We are urging him to form a new cabinet as swiftly as possible and the US stands ready to support a new and inclusive Iraqi government and particularly its fight against ISIL," he said after annual security talks in Australia.

"Let me be very clear, we have always wanted an inclusive government that represents … all Iraqis. That is the goal."

He added that it was important "the forces of Iraq are not a personal force defined by one particular sect and sworn to allegiance to one particular leader, but they truly represent Iraq and Iraq's future in a broad-based sense".

"And I think that everybody understands that is the direction we have to go," he said.

"Nobody, I think, is looking towards a return to the road that we've travelled.

"What we are really looking for here is a way to support Iraq, to support their forces — either training or equipment or assistance of one kind or another — that can help them to stand on their own two feet and defend their nation."

Iraq moved closer to ending Nuri al-Maliki's stubborn grip on power as prime minister on Monday when his own political clan spurned him for Abadi.

Abadi, a Kurd long considered a close Maliki ally, has 30 days to form a government, amid hopes that a broad-based cabinet could serve as a foundation for healing Iraq's deep sectarian divides.

While the US has been conducting air strikes against extremist Islamic State militants in northern Iraq, Kerry said combat troops would not be sent in.

"There will be no reintroduction of American combat forces into Iraq. This is a fight that Iraqis need to join on behalf of Iraq," he said.

But the United States is helping ship weapons to the Iraqi Kurdish forces battling an advance by the jihadists, the State Department said. The Islamic State was previously known as ISIL.

US aircraft have also been airdropping aid to refugees from the Yazidi religious minority who are trapped on a mountain in northern Iraq, surrounded by extremists from the Islamic State.

US Defense Secretary Chuck Hagel said the Iraqi government requested the help.

"As you know, it was the Iraqi government that requested the US assistance with humanitarian delivery," he said in Sydney.

"We agreed with that request. We are carrying out those missions.

"It was also the Iraqi government's request of the United States to assist them with transporting military equipment to Arbil to help the Peshmerga (Kurdish fighters)."

He added that the military equipment being shipped was Iraqi.

"We are — American forces, through CENTCOM — are helping get that equipment to Arbil."

Yazidi MP wounded in Iraq helicopter crash on Mount Sinjar
Kirkuk, Iraq (AFP) Aug 12, 2014 –

An Iraqi lawmaker who helped bring attention to the plight of besieged members of her Yazidi community was wounded Tuesday in the crash of a helicopter delivering aid, officers said.

The pilot was killed when the chopper, packed with rescued Yazidis, crashed during takeoff after delivering aid to Mount Sinjar, two senior army officers said.

Yazidi MP Vian Dakhil, whose emotional appeal in parliament on the plight of people stranded on the mountain made her the public voice of her community, was injured in the crash.

A New York Times journalist also sustained non-life threatening injuries in the crash, the paper said.

Thousands of members of the Yazidi minority are trapped on the mountain in northwestern Iraq with little food or water by jihadists from the Islamic State (IS) group who overran the region.

The UN refuge agency put the number of people on the mountain at 20,000-30,000, while UN minority rights expert Rita Izsak warned they face "a mass atrocity and potential genocide within days or hours."

Insurgents led by IS jihadists launched a sweeping offensive in June that has overrun large areas of five Iraqi provinces and displaced hundreds of thousands of people.

The US military is carrying out air strikes against militants in north Iraq, including Tuesday on a mortar position it said was firing on Kurdish forces attempting to defend Yazidis north of Sinjar.