Terror threat warning not up to scratch: ASIO boss

ASIO director-general Mike Burgess has called for an overhaul of the terror threat level system. (Mick Tsikas/AAP PHOTOS)

Australia's terror threat level could be given an overhaul after the nation's spy boss revealed it was not designed for the current security environment.

In his annual threat assessment on Wednesday evening, ASIO director-general Mike Burgess warned acts of politically motivated violence were becoming more likely, but said the terror threat level of "probable" does not tell the full story.