Australia considering joining anti-ISIS airstrikes in Syria

Australia is considering a U.S. request to launch airstrikes against Islamic State of Iraq and Syria (ISIS) fighters in Syria in an unprecedented departure from Australian foreign policy that could spark political disputes.

Prime Minister Tony Abbott said Friday that his government had received a request from the Pentagon to send Australia's six F/A-18 Super Hornet jet fighters based in Dubai into Syria to attack the militants in their stronghold.

The war planes have been striking Islamic State targets in northern Iraq since October last year. But Australia has balked at war in Syria without the invitation of a legitimate Syrian government or the firm legal basis of a United Nation Security Council resolution.

Abbott said the government had yet to decide on the request, although it is thought the United States does not make such official requests without first gaining an undertaking that they will succeed.

"While there is a little difference between the legalities of airstrikes on either side of the border, there's no difference in the morality," Abbott told reporters.

"In the end, when they don't respect the border, the question is: why should we?" he said, referring to ISIS militants who have declared a caliphate that straddles the Iraq-Syria border.

Opposition leader Bill Shorten said he press Abbott about the legality of an Australian combat involvement during a briefing on Syria next week.

"We will be seeking an explanation of the legal basis upon the proposition which the United States has asked us is it legal, what the United States has asked us to do?" Shorten told reporters.

The government can send fighter jets into Syria without seeking Parliament's permission, although a political squabble could damage public support for a new campaign in Syria.

Don Rothwell, an Australian National University expert on international law, said Australia faced "numerous" legal problems in extending combat operations beyond Iraq.

He said conducting "combat operations in Syria would be going well beyond the remit of the current legal framework."

"The only way in which Australia could really justify this is to say: 'Well look, we're responding to the threat posed by a non-state actor ... and Syria is unwilling or unable to respond to the threat posed by that particular group and accordingly we're going to launch military strikes'," Rothwell said.

But he said that argument is controversial and does not have widespread support in the international community.

United States along with its Middle Eastern allies Bahrain, Saudi Arabia, Jordan and the United Arab Emirates have been striking targets in Syria for months.