US President Barack Obama
US President Barack Obama AFP PHOTO - Saul Loeb

US troops may take combat roles in Iraq

UNITED States President Barack Obama's top military adviser has indicated American troops may take on a combat role on the ground in Iraq in action against Islamic State militants.

In Senate hearings in the US, chairman of the Joint Chiefs of Staff General Martin Dempsey said there was no intention of doing so, but his "recommendation" could change as the situation evolved.

His comments followed Prime Minister Tony Abbott on Tuesday indicating Australia may be involved in operations in Syria, should it be asked by the US.

On Wednesday, the fourth Australian shipment of small arms arrived in north Iraq via a C-17A, and was cleared by Iraqi authorities before returning to base in the United Arab Emirates.

And After Mr Abbott on Tuesday indicated Australia's involvement could cost about $500 million for every six months of operations, Treasurer Joe Hockey reiterated Australia's "obligation" to be involved.

Despite his efforts to address the government's deteriorating budget, Mr Hockey told ABC that the money would ultimately come out of taxpayers' pockets, but the threat was "as much domestic as it is international".

"We have an obligation to ensure that the tentacles of the most evil terrorist group we have ever seen do not extend to our local communities," he said.