The collapse of Stadium Southland after heavy snow in September was caused by engineering faults and inadequate workmanship, a report shows.
The report, issued on Friday, was commissioned by the Southland Leisure Centre Trust, a charitable trust that owns the South Island stadium.
It shows a combination of factors led to the collapse, in one of the worst storms to hit the region in decades.
The head of the trust, Acton Smith, says the collapse can be traced back 10 years to the original plans which were under-designed, and remedial workmanship to remedy that was poor.
Mr Smith says there will be soul-searching on the part of those who built the stadium and legal liability will have to be established by the insurers, NZI.
The report's authors have warned the trust that the engineer who designs the new stadium should be subject to peer review before construction commences.
Remedial work carried out when the stadium was being constructed in 1999 to fix sagging trusses in the roof support system was inadequate.
Ultimately, that work was not able to bear the weight of snow which fell in the September storm.
Concrete columns supporting the gantry truss system were not well detailed and were too small.
Welding associated with the remedial work was not up standard.
The weight of snow on the roof was greater than the building was designed to cope with.
Remedial work defended
The man whose company carried out remedial work on Stadium Southland during its construction is standing by the workmanship.
The report says the stadium was constructed to the building standards of the time regarding snow load.
Noel Fitzgerald, who owned Aorangi Steel at the time, says the 2km of welding was up to standard and engineers signed off on it.
Mr Fitzgerald says the welding needs to be checked using an ultrasound before the blame can be laid at his feet and that only a visual check was made during the investigation into the collapse.
Mayor waiting for Government review
Invercargill Mayor Tim Shadbolt says it is still not known if corners were cut to get the stadium built more quickly and cheaply.
Mr Shadbolt told Checkpoint he hopes a separate review by the Government will come up with some better answers about how it was able to happen.
"I consider this report very much a preliminary report and it just doesn't give us the information to be able to make those sort of judgement calls."