The University of Cambridge has admitted it has “a significant problem” with sexual misconduct after it received 173 complaints in nine months after launching a new anonymous reporting system.

The majority of complaints (119) alleged student-on-student misconduct, while seven complaints were made by staff against colleagues, and two by students against staff. The rest involved neither staff nor students.

The university said it had expected a high number of reports because of the anonymous nature of the system, introduced last May as part of its Breaking the Silence campaign, and viewed the results as “a metric of success”.

Victims at Cambridge and other universities, which have come under pressure to tackle sexual misconduct on campuses, are much less likely to pursue formal complaints. Last term between October and December, Cambridge said just six allegations were formally reported.

Graham Virgo, professor of English private law and pro-vice-chancellor for education at Cambridge, said: “The challenge is that one or two complaints a year do not give a university much information with which to formulate a response to the wider problem.

“Through the anonymous reporting tool, we now have a large number of Cambridge voices who have reported the issues they’ve faced. It supports our belief that we have a significant problem involving sexual misconduct – what we now need to ensure is that those who have been affected receive the support and guidance they need.”

A number of other universities have introduced similar anonymous reporting tools, including Manchester, but Cambridge is the first to publish such a high number of reports.

A feature of the tool is that both the individual who is reporting the sexual misconduct and the alleged perpetrator remain anonymous. The website provides links to support available as well as information on how to make an official complaint. The university said some of the reports related to historic misconduct.

Campaigners in the 1752 Group, set up to address staff-student sexual harassment in higher education, said the Cambridge data highlighted the fear surrounding the use of the official reporting processes in universities.

Emma Chapman, a Royal Astronomical Society fellow at Imperial College London and member of the 1752 Group, said: “We know that many students across the UK do not have faith in official disciplinary processes within their institutions, finding them to be inadequate and discriminatory.

“Anonymous reporting that does not lead to the same neutral investigation as with third or first party complaints will not lead to individual disciplinary action, nor is it clear how it will lead to the culture change necessary to make the university a safer place for students.”

Writing for The Conversation website, Virgo said the figures would be used to judge the nature and scale of sexual misconduct affecting students and staff, and to act on it accordingly.

“Anonymous reporting can help survivors’ voices be heard without their rawest experiences being made public in any way. It gives them a voice in a way that is free of the fear of consequences, but also free from accusations that complaints are vexatious as neither perpetrator nor victim can be named. For some, this may be sufficient. For others, they may want action to be taken.”