ASIO investigates people based on their behaviour, not their background

About 40 foreign fighters have returned to Australia but ASIO reassures the general public about any threat posed

The threat from IS continues but the group has faced significant physical losses Source: AFP

The head of Australia's domestic spy agency says it investigates people based on their behavior, not their background.

The remarks came at a Senate Estimates hearing where senators were being updated on Australia's terrorism threat and other security matters.

The head of the Australian Security Intelligence Organisation (ASIO) has again defended the country's Muslim communities while updating politicians on Australia's terrorism threat.

ASIO head Duncan Lewis, appearing before a Senate Estimates hearing in Canberra, has emphasised keeping perspective regarding the Muslim communities.