Students blocked police officers trying to clear balconies at a Dunedin concert before one collapsed, the Police Association says.
Eighteen people were injured, two of them seriously, when the balcony fell at a gig by the band Six60 in a private courtyard off Castle Street on Friday night.
Police Association president Greg O'Connor said officers told him they and Otago University Campus Watch staff tried to warn students not to overload the balconies, and some took heed.
"There were several students who pointed out to police they had no power to go in to the buildings to try and get people off those balconies, so the police actually had no legal power to do anything about it."
Mr O'Connor said the concert was not an out-of-control situation and police would have been heavily criticised had they tried to shut it down.
Earlier, police said they would not open a criminal investigation into the balcony collapse.
The courtyard is surrounded by student flats, and people had crowded onto roofs and balconies to watch the band. The balcony that collapsed was holding at least 16 people but was said to have been built for up to eight.
A young woman studying at Otago University has been transferred to Christchurch Hospital, with what have been reported as spinal injuries, while a young male student from Otago Polytechnic has undergone surgery at Dunedin Hospital.
Otago Coastal Area Commander Jason Guthrie said police had completed due diligence on available information, and there was nothing to suggest any criminal aspect to the collapse.
While police did not intend to investigate further from a criminal point of view, they would work with the reviews being carried out by Worksafe New Zealand and the Ministry of Business, Innovation and Employment.
'It was just horrible'
One of the students hurt when the balcony collapsed said she'd never have stood underneath, had she realised how many people were on it.
Otago University student Lauren Tye told Checkpoint with John Campbell she had to crawl out from the wreckage, but was one of the lucky ones.
"From what I could see there were about five of them just kindof flat on the ground and to me they looked unconcious, and the other two girls I was with were sitting beside me and they were just in so much pain.
"The look on the student's faces around us made it more real. It was just horrible."
New tools needed to keep students safe - mayor
The collapse has given urgency to wider efforts by the authorities, with the Dunedin City Council conceding it needs to take a wider look at student safety issues.
Mayor Dave Cull said the event was organised by students and a commercial sponsor, but neither the students' association nor the council was consulted.
Action was urgently needed to ensure people's safety and preserve the reputations of the city and Otago University, he said.
Mr Cull said he would meet representatives of the university, police and other agencies to look at what happened during orientation.
He told Morning Report the city and the university needed to do more to keep people safe.
"We need to take control of this and it may be that we need new tools."
Up to 1500 people could turn up to parties in a very short space of time, he said.
"This is a unique situation. We have the greatest concentration of young people in any suburb in the country."
The council had no power to control the event at which the balcony collapsed as it was held on private property, and that might need to change.
"Rather than asking what powers do we have, we may need to ask 'what outcomes do we need to get?'
"It could be about shutting things down or preventing things, or having some kind of protocol."
Mr Cull said a precedent was the regular party on Hyde Street, which had got out of hand in the past, but the university, the council and the students' association had since worked together to make it safer and more enjoyable.
Balcony 'met building standards'
Mr Cull said the council's chief building inspector had examined the balcony yesterday, and said it met the requirements of the building code.
"I welcome the [Department of Building and Housing's] further investigation to make it absolutely clear what caused it."
He said whether the partygoers were jumping up and down on the balcony was not the issue; it was that hundreds of people turned up to an event that would not normally be held in a domestic venue.
"It's just not acceptable to expect those kind of situations to not present more risk than if it's professionally organised."
He added the University of Otago put an enormous amount of effort into pastoral care, including having the "harshest code of conduct" in New Zealand, but it was not enough.
"It's too much to expect the university to take responsibility for all the activities of lot of people outside the academic environment."
He said the problem needed a city-wide approach.
"The whole community needs to take responsibility, and responsibility for the solutions to this."
The health and safety regulator says it won't be investigating the balcony collapse.
A WorkSafe inspector has been to the site and ruled the fall did not happen at a workplace.