A photo taken inside the flat shows partygoers packed on the ground floor and internal balcony and staircase.
The student said at one point a “scrap” broke out on the balcony that almost caused people to tumble down the stairs.
“There could have easily been someone trampled on a stairwell,” they said.
The View St party was held at a converted former backpackers which has previously made headlines for out-of-control parties.
Senior sergeant Anthony Bond, of Dunedin, said officers were called to reports of bottles being thrown at the party about 11pm on Wednesday.
The numbers packed into the building presented a safety hazard and police took a prevention approach, turning off the stereo and clearing out the party, Bond said.
It took about an hour to remove partygoers.
A 20-year-old man was arrested for urinating on a police car and referred to the University of Otago proctor.
A university spokesperson said the proctor visited the address yesterday and spoke to tenants.
“Campus Watch staff are actively working in the North Dunedin community 24/7 throughout Orientation Week and were not made aware of this event in the city centre.”
It said it took the safety of its students seriously and was the only university in New Zealand to invest in a 24/7 service like Campus Watch.
The university did not respond to a question about whether the party was disappointing in the context of the Sophia Charter, which was set up following her death.
The multi-agency agreement included police working with the university to establish a clear set of working principles regarding large parties and gatherings.
Asked about a permanent noise abatement notice previously issued to the address, a Dunedin City Council spokesman said it was “actively investigating” the latest issues.