Protesters who trashed the Adelaide office of hardline conservative Liberal Senator Cory Bernardi over his opposition to the controversial Safe Schools program could face criminal charges.
A group on Friday overturned furniture inside the senator's Kent Town office and scrawled slogans including "Australia's Trump", "f*** Bernardi" and "no to homophobia" around the building.
Senator Bernardi called the protesters, thought to be from Social Alternative, "a bunch of cowards".
"Lefty totalitarians have trashed my office and threatened my staff because their agenda has been exposed," he tweeted.
"Gutless actions like this will never stop me speaking the truth. Grateful my team are safe and appreciate the efforts of police."
Police are now reviewing CCTV and witness statements to determine if the protesters should be charged.
One was reported for defacing a road sign with graffiti.
Mr Bernardi is fiercely opposed to the Safe Schools program, which was designed to reduce bullying of LGBTIQA students and was the subject of an independent review.
The Australian Christian Lobby said the protest showed a "disturbing lack of tolerance".
ACL managing director Lyle Shelton said while everyone had a right to express their views on the Safe Schools program, no one should resort to violence or bullying.
"Storming the office and intimidating staff with violent action while Senator Bernardi is away in Canberra for parliament is despicable and cowardly behaviour," he said.
SA Labor MP Chris Picton spoke out against the protest, tweeting "once again Socialist Alternative does something completely idiotic and counterproductive. They never learn."