An Australian Special Forces soldier has died overnight in Afghanistan in what the Australian Defence Force believes is a non-combat-related incident.

New Defence Force chief Mark Binskin told reporters in Canberra on Wednesday that the soldier was serving at the Kabul headquarters.

The soldier's colleagues found him about 2pm Afghanistan-time in an administration room with a gunshot wound, Air Chief Marshal Binskin said.

''His injuries were too severe and he later died surrounded by his mates,'' Air Chief Marshal Binskin said.