For the first time in at least five years, Sydney University's student union (USU) has defunded an event being held by one of its own clubs, on the ground it promotes sexual violence.

The Red Pill is a documentary following a woman who identifies as a feminist and then renounces the title after learning about the struggles men face in America. "I will no longer call myself a feminist," she says at the end. It promotes the idea that men's issues go overlooked because when men complain they are shut down by 'feminists'. It's very popular with Men's Rights Activists (MRAs).

It features MRA Paul Elam, who once wrote in a blog post (now deleted) that some women have a "please rape me neon sign" glowing above their heads.

How a petition to stop a film became a massive own goal You would probably never have heard of The Red Pill if a small group of feminists hadn't protested its screening.

In the past, campaigns to ban the screening of The Red Pill have helped publicise the documentary; a private screening in Melbourne last year sold 60 tickets and was canceled after a petition of more than 2,000 signatures. Other screenings have met similar opposition.

The Conservative Club, Students for Liberty, and the Brotherhood Recreation and Outdoor Society (BROSOc) planned to screen the film on May 4 using union resources. The Facebook event page had about 40 people going and 40 people interested. The three clubs have between about 70-100 members each, and are designated as 'small clubs', according to the USU.

There are about 60,000 students at Sydney University and 17,000 Union members.

The Union learned about the screening late last week and sent an email to the organisers yesterday informing them the event would be defunded; the decision does not stop the organisers from screening the film on campus.

The organisers have framed the decision as a blow to free speech.

Renee Gorman, a journalism student and a member of all three clubs organising the screening, said the screening had meant to provoke debate.

"Us putting this on campus is not saying we 100 per cent agree with what's in this film," she said.

"University is for having healthy debate, not for shutting them down.

"I don't think this film does discriminate or harass people."

She said the defunding breached the USU's own guidelines to not exclude clubs because of their politics and that a screening will go ahead on campus.

This is about sexual violence, not debate: Union

USU Honorary Secretary Shannen Potter told Hack the film breached a regulation that funds may not be used for activities that discriminate or harass on the basis of sex.

"We by no means want to shut down debate," she said.

"We're very happy for the community at large to have debate on these issues - we're a member based organisation and our funds come from members. If something breaches our regulations we're under no obligation to give it a forum."

"We're happy for you to have it but we don't have to pay for it."

"This is not a discussion about debate - this is a discussion about sexual violence."

She said the union had received complaints about the screening and she had subsequently watched the film herself and investigated its claims.

"Some of the content in the film is to the point where it's physically threatening for women on practice. There's an implied threat of sexual assault."

"To us, sexual assault on campus is a massive issue. Protecting women from sexual violence and threats of sexual violence is the most important priority."

She said it was the first time in at least five years the union has defunded an event of one of its clubs on the ground it discriminates or harrasses.