Protesters may target a mass vaccination clinic in Canberra on Saturday when their demonstrations against COVID-19 mandates culminate.
People have been gathering in the ACT for a fortnight to protest various grievances, in particular their opposition to mandatory vaccination policies.
Demonstrators suggested protesting at the "Superhero Saturday" event at the vaccination clinic at the Australian Institute of Sport.
The plan was discussed at their main campsite at Exhibition Park in Canberra's north, and shared on social media.
ACT Policing's Commander of Operations, Linda Champion, said police were aware of the threat and monitoring the demonstrators.
"We don't anticipate anything unlawful going on, but we [will be] there in sufficient numbers to ensure the safety of all parents and children turning up to the clinic," she said.
ACT Chief Minister Andrew Barr said the protest threat was "very disappointing".
"That's the sort of extremist behaviour that we've been calling out every single day," he said.
Mr Barr also suggested the "eclectic" protesters lacked the numbers and cohesion to follow through their threats.
"There's been a lot of social media big-talk that hasn't really come to fruition," he said.
Campers given deadline to leave Exhibition Park
Saturday's planned protests follow disruptions throughout the week, when some demonstrators blocked traffic and allegedly harassed local businesses and residents who were complying with public health orders.
A small number of protesters have threatened violence against politicians, while domestic spy agency ASIO warned this week that the anti-vaccination mandate movement had radicalised some people and exposed them to "extremist messaging, misinformation and conspiracy theories".
The presence of demonstrators camping at Exhibition Park has also hampered the Capital Region Farmers Market and Lifeline Canberra's annual book fair.
The book fair is using the venue this weekend for its 50th birthday event, but the market has been cancelled due to concerns about safety.
The market's organisers said the closure was "a devastating result for our farmers and producers following on from the last two years".
Mr Barr said the protesters must leave Exhibition Park on Sunday, when their booking expired.
He said a camping fee of about $25,000 had been paid but the bulk booking would not be extended, as Exhibition Park must be prepared for the Canberra Show.
"That notice has already been publicly given and, obviously, we need the showgrounds vacant for the show … from Monday," he said.
Mr Barr said police would act if the protesters refused to move, citing the removal of an illegal campsite in the parliamentary area last week.
"Police are ready and we have the numbers to move on any of the last stragglers who don't move on at the conclusion of their rental agreement to hire the campground," he said.
Police said the protests had been mostly peaceful over the past fortnight, though a large number of officers would be deployed to monitor Saturday's demonstrations.
Canberrans are advised to avoid the parliamentary area and to consider using public transport to access the book fair.
