Hundreds of students gathered for a makeshift toga party two weeks ago, and more returned for another large gathering last weekend.
Mattresses were thrown around, people urinated in bushes, and the field was left strewn with rubbish and broken glass.
First-year hall resident Molly said the organisers and attendees were largely other student residents, and that the hall's strict alcohol bans pushed people to drink in public spaces.
With community cases surging, she said the gatherings made some residents feel more anxious about getting Covid-19.
"I was definitely keeping my distance because I didn't want to catch it, and it was definitely a superspreader," she said.
Third-year geography student Natalie O'Connell was one of the few students choosing to work from the campus this week, and said it was clear the party-goers didn't care about the effect their actions were having.
"People are going out of their way to get mass gatherings of definitely more than 100, no one's checking vaccine passes, no one's on security, so it's all round pretty irresponsible, and they know it," she said.
University of Canterbury executive director of people, culture and campus life, Paul O'Flaherty, said he was concerned by the harmful behaviour.
"While a healthy social life is often part of student life, events that become unsafe for students and impact negatively on UC's neighbours are not acceptable."
He said the security presence had been increased, and the university was working with the police to find solutions.
Regular meetings throughout the year are held with the community to discuss matters relating to the university neighbourhood.
'Tough time for students'
University of Canterbury Student Association president Pierce Crowley was sympathetic to those who attended, citing the lack of Orientation Week events as the driver of alternative gatherings.
"It's a really tough time for students. For many of them, this is their second or third year of disrupted learning," he said.
"This [the partying] hasn't happened in the past, and that's because we've been able to host events that have got it out of people's systems in a big burst at the beginning of the semester."
He said the association was focused on educating students on the legal requirements of gatherings in the red traffic light setting.
Co-editor of the university's student magazine, Ella Gibson, thought more could be done now to give students safe partying options.
"There's definitely a gap in the fun infamous night-time drinking events," she said.
She thought the party-goers were on the right track in using Ilam Fields, and that the area could be used for controlled night-time events within the current Covid-19 guidelines.
Crowley said the restrictions made it too difficult to host any large events safely now, but a priority for the association was hosting replacements to Orientation Week events as soon as it was possible.
"We're really keen, once we have the ability to do so again, to host these events and get it in a supervised environment where students can party safely and stay out of the community's hair."
- RNZ