Greens candidate Connor Parissis says he confronted a group of "Vote No" campaigners in 2017, who were claiming that marriage equality would lead to "paedophilia and bestiality".
The Greens candidate for the Sydney seat of Barton has defended his behaviour during a protest when he told Christian university students their beliefs were a joke in an expletive-laden spray.
On Wednesday, footage emerged from 2017 of 21-year-old Connor Parissis yelling at a group of Christian students at Sydney University opposed to same-sex marriage.
"Go back to church ... You know who's a joke? Your f*** beliefs," he yells, before adding other expletives.
The video shows Mr Parissis confronting the students and yelling and pointing at them, before another man tries to calm the situation.
Mr Parissis said descriptions of his behaviour in The Australian, which first reported on the video, were incorrect and did not tell the full story.
In a tweet, he alleged the group were "Vote No" campaigners who were "telling passerbys that marriage equality would lead to legalised paedophilia and bestiality".
"As the elected 2017 Queer Officer of Sydney University, it was my responsibility to confront hate and bigotry," he said.
"I stand by my right to protest and counter-protest."
Mr Parissis said the News Corp stories had "incited threats of violence" against him, "all of which have been recorded and will be reported".
"Transgender youth homelessness is at unprecedented rates, refugees are still locked up in detention and our planet is dying. But instead we're talking about this," he said.
SBS News contacted the Greens who said neither the party or Mr Parissis would talk further about the matter.
On the Greens website, Mr Parissis describes himself as a "left-wing activist, student and writer who believes in a better world".
"At age sixteen, I came out as gay, and have struggled with these two identities ever since. Now, a local from Canterbury, I am running to be the progressive voice that has, for so long, been absent in Barton," he says.
Mr Parissis has already come under fire this campaign, having to apologise for social media posts including one which encouraged violence against "racists" and "Islamophobes".
Barton is considered a safe Labor seat, which the party won by 8.3 per cent in the 2016 election.