A balcony that collapsed at a Six60 concert in Dunedin, injuring 18 people, was built to code and was well maintained, the Dunedin City Council says.
The Friday-night concert was called at the last minute in a courtyard of a private property near to 660 Castle St where the band once lived and took its name from.
Word spread on social media and about 1500 people crowded into a small space, perching on roofs and standing on balconies.
Simon Pickford, the council's general manager services and development, told NZ Newswire a council staff member inspected the site on Saturday morning.
"The initial finding based on the investigations we've done today is the deck was built as per the plan, which is to the New Zealand Building Code.
"There were no maintenance issues picked up. It was purely a structural failure due to overloading."
He said the deck could hold about seven people and there were 12 to 15 on it when it collapsed on people below.
The property was built in about 2000 and was in good condition.
Mr Pickford said the council, the University of Otago and police only became aware of the Six60 concert "at the last minute" on Friday.
It was a spontaneous event and the band had played last year at a more appropriate venue.
He said the way the concert was called and its location were issues to be followed up.
"We work really closely with the university, police and the student union to have these events in a safe environment.
"It was an unfortunate circumstance which meant a lot of people gathered in the wrong place," he said.
Residents of adjacent properties with the same balconies are being told not to use them while the council investigation continues.
The council couldn't require the other balconies to be strengthened because they were to code but there would be a discussion with the building owners, Mr Pickford said.
At least two people spent the night in Dunedin Hospital in a serious condition after the balcony collapsed and fell three metres to the ground.
Fourth year student Tahnae Wilson-Brown was just metres away when the situation unfolded and says there were some gruesome sights.
"We'd seen one guy [whose] foot was facing the wrong way. He had a compound fracture in his leg, and it was just like, ugh, definitely the sort of thing you don’t want to see, ever."
Eighteen people were taken to hospital. Two were badly hurt enough to be admitted and were in a serious but stable condition, the hospital said late last night.
Four had already been discharged and the others were being assessed.
Police say they were trying to clear people from the roofs and have fewer on the balconies when the disaster happened.
People were thrown to the ground and the decking landed on people in the courtyard.
Photographs and videos emerged on social media of the balcony completely detached from a modern property and then those in the crowd lowering it to the ground.
Six60 tweeted that the band had continued to play on the advice of security and police.
Pictures and video show dazed and injured people on the ground around the collapsed balcony being helped by others and emergency services.
Otago University Students Association spokesperson Tess Trotter says students were quick to help out emergency services.
"People on the ground were incredibly helpful, there were students moving cars out of the way, and I've seen a lot of response on social media from students talking about how fantastic the police and safety services were," she said.
Police say WorkSafe New Zealand will visit the site to determine the cause of the balcony collapse.
North Dunedin is dominated by the University of Otago and it's the start of the academic year.
NZN / Newshub.