Australia is considering a U.S. request to launch airstrikes against Islamic State fighters in Syria in an unprecedented departure from Australian foreign policy that could spark political division at home.

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 says the government had yet to decide on the request. Opposition leader Bill Shorten questioned its legality.