Anti-government extremists known as "sovereign citizens" have been identified as a potential terrorism threat in Australia by a confidential New South Wales (NSW) Police report.
The NSW Counter Terrorism and Special Tactics Command assessment suggests there are as many as 300 sovereign citizens in the state, and that their numbers are growing.
It also suggests they have "the motivation and capability to act against government interests and should be considered a potential terrorist threat".
Police records show the number of Australians identified as sovereign citizens in NSW doubled from 2009 to 2011 and nearly tripled from 2009 to 2012.
Interactions with police increased 50 percent in 2011, with a "notable increase in threats of violence".
In the United States, the Federal Bureau of Investigation (FBI) classifies sovereign citizen extremists as domestic terrorists and the US Department of Homeland Security has listed them as the number one domestic terror threat in America.
Detective Superintendent John O'Reilly, who is the commander of the NSW Counter Terrorism and Special Tactics Command, said police had been examining overseas trends and threats.
"Sovereign citizens are people that don't buy into our legal framework, our system of government," he said. "They consider themselves individuals and operate outside the law and outside our tax system."
Police intelligence of incidents involving sovereign citizens in Australia ranges from displaying homemade registration plates and "plans to use paint bombs to disrupt court proceedings", to making plans to kidnap a judge, judicial officials and a police officer.
The report also states, in 2012, sovereign citizens threatened to burn down the home of a judge and "cause harm with firearms" and had "plans to murder sheriff officers if they attempt to seize property".
While Mr O'Reilly stressed Australia had not experienced any of the high impact violence resulting in death or casualties associated with the movement overseas, he said there were indications of radicalisation.
"A number of instances have ended up in people being placed under arrest and sometimes there has been a degree of resistance on the basis that they claim that the police officer has no authority over them," he said.
"We are always conscious of preventing terrorism and we are mindful of any movements that have the potential to go down that path."