The US-led military campaign against Islamic State forces in Iraq has been "remarkably successful" in its first four months, according to one of Australia's most experienced war veterans.

Retired Major General Jim Molan, who commanded Australian troops in Iraq in 2004, urged Australians to be realistic about the speed of progress against the Islamic State of Iraq and the Levant (ISIL) and rejected claims the military campaign has done little to turn the tide against the terrorist group.

A Royal Australian Air Force F/A-18F Super Hornet taxis to begin another mission in the Middle East. Credit:Andrew Eddie

Mr Molan was speaking to Fairfax Media as part of a survey of defence analysts on the success of the campaign so far and the prospects for 2015.

The US-led Coalition has launched 500 air strike missions on ISIL forces, including more than 180 sorties by Royal Australian Air Force F/A-18F Super Hornets, according to the Department of Defence.