One building was so bad it was pure luck no one was killed, and others have had to be shut down, concrete investigators have warned officials.
The Ministry of Business, Innovation and Employment is playing down any risk to public safety, despite being only partway through an inquiry.
It has been looking for the last month into the findings of Concrete Structure Investigations.
RNZ was first to report on the company's findings, that most of the 1200 buildings it had scanned since 2014 have structural problems, some very serious.
Watch Phil Pennington's report from last month:
Building Minister Jenny Salesa ordered officials to verify the findings and had asked for daily updates.
It was still trying to but needed more information, the ministry said.
The company questioned that. It had given the ministry a list "where emergency action was taken to avoid public disaster" in several cases, company director Jane Roach-Gray said.
"So talking about 'no risk to public safety' is a little bit misleading. Yes, the buildings that have been checked, have had action to protect public safety, so the ones checked are not the issue."
The question was "what else is out there that is not known and what has gone wrong to have this situation in New Zealand structures".
The list of recent scanning cases had individual building names and locations blanked out, but included:
- Six jobs where the use of the structure for the public was closed immediately or evacuated
- In one of those the company "and the structural engineers were surprised nobody had been killed - it was pure luck"
- Eighteen structures where she had concerns about their team even going in
- One, subsequently closed down, where only the company directors went in because "it looked like Chernobyl and could fall down any minute"
- One commercial building was urgently propped to support the frame
- One "life-care asset" was closed permanently and a second took months of expensive retrofit to reopen
- One commercial building had double system fail in earthquake
- Three jobs went into litigation because there was enough poor practice by the contractors or consent systems to seek compensation
However, the ministry said it awaited "information on specific buildings" and the issues the company "claimed to identify".
"We cannot assess whether there is sufficient information to warrant further enquiry and/or investigation before we receive this," said its manager of building system assurance Simon Thomas.
The company said it would not identify individual buildings.
"Identifying them would be unfair and pointless as their buildings have been remediated. It is also outside the terms of [our] contracts with clients," Ms Roach-Gray said.
The ministry expected to get more redacted data by the end of the month, then it would assess what to do next, Mr Thomas said.
While it was true some buildings had shown signs of stress, which was why engineers called their scanners in, in other cases it was just that an engineer became "suspicious" of the plans, or found one structural part missing, only for scans to reveal many other problems, Ms Roach-Gray said.
The company had offered to undergo tests from the ministry to prove its skills, she said.
It was also calling for mandatory minimum standards in the scanning industry as currently there weren't any, she added.