Pilot safety tops Syria considerations

Defence Minister Kevin Andrews has asked for detailed advice on pilot and air crew safety before signing off on air combat missions over Syria.

Key concerns are the ability to rescue crew if they are shot down, and keeping out of the way of other aircraft in the increasingly crowded skies.

Mr Andrews said the safety of RAAF pilots and aircrew would be foremost in the government's mind as it considers extending existing air operations over Iraq to include Syria.

The national security committee of cabinet will canvas the two safety issues when it meets to consider the request from the United States early next week.

"That will be something we will be looking at," Mr Andrews told reporters in Canberra on Thursday.

"I will be getting advice about that from defence, and that will be squarely before the national security committee when we come to consider this matter."

Six Australian F/A-18 Hornets now conduct combat missions over Iraq, along with a E-7A Wedgetail airborne warning and control aircraft and a KC-30A airborne refuelling aircraft.

Mr Andrews said no Australian aircraft had yet flown across the Syria-Iraq border.

But Islamic State terrorists did not respect any regional border, he said.

"The request from US (defense) secretary (Ash) Carter is specifically in relation to the fight against Daesh and into Syria," he said.

"The area of any further operation, if we agree to it, would be in that eastern region of Syria specifically against Daesh."