RAAF pilots are poised to begin flying deadly American Reaper drones over Syria, taking for the first time Australia's involvement in the fight against the so-called Islamic State from Iraq into the more complex neighbouring country.

A Defence spokesman has told Fairfax Media that five RAAF personnel are embedded with the United States Air Force's 432nd Operations Group, which flies armed MQ-9 Reaper drones.

An unmanned US Reaper aircraft.

"While the focus for [Australian Defence Force] operations to counter Daesh remains Iraq, a small number of Royal Australian Air Force personnel are now contributing directly to coalition operations to counter Daesh in Syria as well as Iraq, consistent with long-standing arrangements for ADF personnel embedded in US units," the spokesman said, using the alternative name for the Islamic State.

He said five RAAF personnel attached to the USAF were "performing operational duties with their parent unit as MQ-9 Unmanned Aircraft System pilots and sensor operators".