Despite being hailed as a success by many, including Dunedin Mayor Dave Cull, drunken incidents marred the event and led police to say the event was ''far from being what police deem a safe event''.
• Slideshow: Hyde St keg party
In one incident, an intoxicated man vandalised three vehicles including a St John rapid response unit, police said.
The man shoulder-charged the St John vehicle's windscreen about 4pm in Albany St, showering the female paramedic, who was driving it, with glass.
''This is yet another example of the harm alcohol causes and the poor decision-making of those under the influence,'' Coastal Otago area prevention manager Inspector Mel Aitken said.
''Despite the best efforts of organising staff to create an enjoyable occasion for students, the level of alcohol-related harm and the risk to public safety still remains too high.''
A dozen people were arrested on a variety of charges including assaulting security staff, fighting, disorder and offensive behaviour, and about 50 people were treated by St John staff for the effects of intoxication and injuries.
St John Coastal Otago area manager Doug Third said the mood of party-goers was ''generally good''.
''Later in the day, there were some reasonably grossly intoxicated people we saw, which was disappointing,'' he said.
Two people spent more than four hours detoxing with St John staff and another two people were taken to Dunedin Hospital because of injury.
''They wouldn't have been injured if they weren't intoxicated,'' he said.
A Dunedin Hospital spokeswoman said at least six people presented to the hospital's emergency department in conditions directly linked to the student party.
''Quite a few others'' were treated at the department and could have been linked to the party, but Saturday was no busier than usual, she said.
No-one was admitted to hospital.
Otago University Students' Association president Paul Hunt said the association was pleased with crowd behaviour in general and arrests were similar to previous years.
He was saddened by the attack on the St John vehicle.
''It is terribly disappointing to have the actions of a small number of people cast a poor reflection upon the many party-goers who had a safe and enjoyable time,'' he said.
''OUSA became involved in the Hyde St party to help co-ordinate safety measures to keep both the attendees and the staff working on the front line of these services safer; which is why this particular incident is so disappointing.
''We are, of course, always aiming to lower the number of incidents through the measures put in place, and will continue to work collaboratively with all the stakeholders towards achieving this aim.''
It was too early to comment on the future of the event or what, if any, changes would be made.
University of Otago vice-chancellor Harlene Hayne said the majority of students were well-behaved.
''No-one climbed on the roofs and there was not a shard of glass on the street,'' she said.
''Unfortunately, despite the best efforts of OUSA and dozens of volunteers, a few party-goers caused problems. The incident with the St John transport vehicle is distressing and unacceptable to everyone in the community.
''If the person who carried out this act is a student at the university, they will be subject to the Code of Student Conduct.
''I remain concerned about the problems caused by excessive alcohol consumption which will not change until we address New Zealand's permissive laws regarding purchase age, price, access.''
When asked about the future of the event, she said: ''We will continue to work with all stakeholders to provide fun and safe events for students in the future''.
Mr Cull said he understood the event was ''as well-behaved and successful as any has ever been''.
''There were 12 arrests ... which is pretty successful given what it was - 4000 students drinking too much,'' he said.
''But the problem is in our community there is still a problem around alcohol and that's not just a student issue; it's a community problem.''
He could not comment on what changes he would recommend to the running of the event or its future, but he was ''not wedded to the idea of the Hyde St keg party at all''.
Insp Aitken said police were confident improvements could be made to make the event a ''safe and enjoyable social occasion for all students''.
Anyone with information on the man who attacked the St John vehicle or who witnessed the incident should contact police on 471-4800.
Information can also be provided anonymously to the organisation Crimestoppers on 0800 555 111.
