Terror threat won't go away as IS declines

The chief of Australia's spy agency has warned the decline of Islamic State won't eliminate the threat posed by violent extremism.

"This ideology that is being pushed by IS will continue to be promulgated by individuals and groups that adhere to these violent and misguided beliefs," ASIO director-general Duncan Lewis told the Australia Strategic Policy Institute's counterterrorism yearbook launch in Canberra on Tuesday.

There are more than 100 Australian citizens fighting for IS in Iraq and Syria, with 64 confirmed dead.