An "escalating threat" to the community has forced counter-terror police to raid numerous homes and arrest a man in Victoria.
Police say the 31-year-old man in custody was attempting to harm Victorians and producing documents that would incite people to harm others.
They would not confirm the man was a member of far right group Reclaim Australia, but said "the individual in custody has a number of affiliations to different organisations".
Counter Terrorism Command Assistant Commissioner Ross Guenther says there were growing concerns actions were escalating.
Police executed four warrants across Melbourne and rural properties on Saturday.
Forensic investigators will be collecting evidence for the next 24 hours at the Braybrook address in Melbourne's west where the 31-year-old was arrested.
Mr Guenther said no other arrests were expected at this stage.
The man in custody is known to police.
Tip-offs from the community via the national security hotline were helpful in the joint investigation by Victoria Police and the Australian Federal Police.
No charges have been laid yet.
