The university has released the results of a September 2015 survey of almost 2000 students, which gathered anonymous information about student experiences of stalking, sexual harassment and sexual assault.

Twenty-five percent of students reported experiencing some form of unwanted sexual harassment or assault while they were at university, with the majority of incidents occurring off campus. 6.2 percent of all respondents had experienced an incident on campus or at a University-related event.

Female students were at significantly higher risk than males, with 40 per cent of women reporting at least one incident of unacceptable behaviour since enrolling at university. 12 per cent said they were victims of stalking, 1.6 per cent said they were raped, 5.1 per cent sexually assaulted, 4.2 per cent reported being in an abusive relationship and 17 per cent were sexually harassed.

But 57 per cent of respondents were not aware of the university's procedures for reporting sexual harassment or assault, or knew where to seek support after a sexual assault.

"A relatively small percentage (eg 1.4 per cent or less) of even the most serious incidents are reported. The rate of reporting within the university was 1 per cent of incidents reported to an official on campus," the report says.

Of the tiny fraction of students who did report an incident to the university, more than 40 per cent said the university's formal procedures did not help them deal with the problem - a proportion that "requires serious consideration", the report says.

Jordi Austin, the university's director of student support services, said while the survey suggested the numbers of serious incidents on campus were lower than the rate in the broader community, "any incident that goes unreported is a cause for concern. It means that there are people out there who have conflicted feelings about what happened to them, or are unsure whether ... there's any utility in reporting to the system".

It comes three months after Universities Australia launched a national campaign to strengthen universities' responses to sexual assault and sexual harassment after US documentary The Hunting Ground cast light on the largely unspoken problem of sexual violence on campuses.

The University of Sydney's women's officer Anna Hush is critical of the university's support services for victims, saying there was no "specific procedure for reporting sexual assault on campus".

"There's a general complaints procedure that is university wide, it's incredibly generic, also covers things like academic misconduct and intellectual property," she said. "It's a form on the website that you fill in, so you have no idea where that information is going, whereas a lot of these [complaints would be] sensitive and confidential.I think there need to be trained staff on hand and a specific process for dealing with this."

The university's Ms Austin said that the student affairs office could help victims find appropriate support but were obliged to refer students to the police.

"Given that sexual assault is a crime, the university needs to direct all incidents of a crime to the police. We do understand that not all students or victims of crime feel that is appropriate for them. So the other portal we make available as a very important first response is through the sexual assault clinics established in NSW - they have the expertise to help people determine what they want to do. ... Then if student feels they want to move forward they can be directed to the complaints portal."

The university is now reviewing its complaints protocols to simplify points of contact and procedures for incident reporting. Student feedback indicated some victims were simply seeking academic support such as special consideration while they dealt with the fallout from an incident.

UNSW Professor Andrea Durbach, who runs the Strengthening Australian University Responses to Sexual Assault and Harassment Project, said under-reporting of such incidents is not confined to universities but corresponds with broader social patterns, because victims can be reluctant to come forward for a number of reasons. In partnership with the NUS, the Australian Human Rights Commission and Universities Australia, the project aims to improve processes for reporting and resolving such incidents across the university sector.

In an opinion piece for Fairfax Media, UNSW Vice-Chancellor Ian Jacobs says the university sector is taking a national approach to the problem. "We do not yet have comprehensive data on the frequency of sexual harassment on university campuses in Australia, or know whether universities are any more or less safe for our students and staff than the rest of Australian society. We can, however, all agree that no level of sexual harassment or assault at our universities is acceptable." The Australian Human Rights Commission will conduct a national survey of university students to "build a comprehensive national picture of the prevalence and nature of the problem," he writes.

The release of the survey on Tuesday follows a string of media reports of incidents of sexism and "slut-shaming" at Sydney university's Wesley College. However, more than three-quarters of respondents to the survey said they felt safe on campus.

In February the National Union of Students released the results of a survey where 27 per cent of female students reported they had experienced sexual assault, of which 18 per cent reported rape, or attempted rape.