Australians "can't be complacent" over a Capitol Hill-style incident on home soil after open threats to politicians, the head of a key security committee has warned.
Liberal senator James Paterson, chairman of the powerful Parliamentary Joint Committee on Intelligence and Security, has joined a growing chorus of politicians voicing concerns over their safety, confirming he had altered his security arrangements "quite significantly".
Senator Paterson told The Canberra Times lockdowns had accelerated radicalisation, with would-be extremists spending more time online and away from stabilising human interactions.
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He urged Australians to take "very seriously" a rise in threats against politicians and their families.
"Things that perhaps people might have said in a pub once to let off steam are now being well-documented online," he said.
Senator Paterson said it was no surprise Melbourne was the epicentre, with many protesters expressing an "absolutely sincere and genuine anxiety" over the state's hard-line pandemic response.
But some elements were seizing on their frustration to introduce extremist ideologies, he said.
In scenes reminiscent of the January Capitol Hill riots in Washington DC, protesters erected a makeshift noose and used a doll of Mr Andrews to attempt a mock-execution.
Police were investigating a number of threats made against Victorian MPs, and have charged a man who allegedly encouraged protesters to bring firearms to the rally to attack the Victorian Premier.
Senator Paterson argued Australian political culture was not infused with the "strong revolutionary self-identity" seen in the US, which made a Capitol Hill-style incident less likely in Australia.
"I'm hopeful that nothing of that severity would happen here. But we can't be complacent about it, we can't just assume that it won't happen," he said.
"I'd hope that it's less likely, but it doesn't take an awfully large group of people to do something like that, to overwhelm the security ... at our parliaments.
"It's something that certainly Victoria Police and the Federal Police in Canberra do take very seriously."
Senator Paterson's staff had seen an increase in threats, and he has changed his personal security arrangements "quite significantly" over the past two years.
"I don't want to overstate it, and I don't want to appear too sympathetic to myself, but I do have concerns about my safety and that of my staff and my family," he said.
"The more of a high profile you have, and the more you're involved in national security issues, the more attention is drawn to you from a range of elements."
Senator Paterson, who was barred from entering China after speaking out against the Chinese Communist Party's abuse of the Muslim Uyghur minority in Xinjiang, said those elements were both state and non-state actors.
'No place': Violent threats condemned
Prime Minister Scott Morrison has been accused of pulling his punches over the protests in a bid to appease anti-lockdown protesters.
Mr Morrison on Thursday said there was "no place" for intimidation in public debate, urging civility and respect.
"Where we have disagreements, we don't handle them with violence. There can be no tolerance for that," he said.
But Mr Morrison also accepted many Australians were frustrated after two years of lockdowns.
"Over the last couple of years, governments have been telling Australians what to do," he said.
"Now there's been a need for that as we've gone through the pandemic, but the time is now to start rolling all of that back."
Labor frontbencher Ed Husic accused Mr Morrison of pulling his punches in an effort to curry favour with extremists.
"It seems, like with Trump, Scott Morrison doesn't want to upset violent extremists," he asked the ABC.
"Why? Is it because he wants to curry their votes? Today was not the day for him to exercise some sort of moral equivalency."
Mr Andrews on Thursday insisted Victoria was not a "state of division", saying its vaccination rate above 90 per cent showed Victorians were "united in our belief in science".
"[But] there are some extremists out there that are putting [out] just intolerable views. I can't say much more because Victoria Police have charged some of them, as they should," he said.
"That's not democracy, that's something very, very different."
It comes amid increasing concern over the safety of Australian politicians, with Labor MP and counter-terror expert Anne Aly urging colleagues to undergo a "stocktaking" of their personal security.
WA Premier Mark McGowan on Wednesday revealed a man had approached his office armed with a machine gun, while NT Chief Minister Michael Gunner was forced to move his family after their home address was posted online.
Health Minister Greg Hunt has also revealed his children had been threatened "quite openly".