Only 10 buildings in Porirua have been checked by the council for building safety systems compliance in three years, far short of the roughly 330 checks recommended.
The city north of Wellington has 437 buildings that have warrants of fitness covering 16 types of systems including emergency warning systems, fire sprinklers, lifts, emergency lights and smoke control.
The Ministry of Business, Innovation and Employment recommends checking about a quarter of the stock each year, so Porirua should check about 110 annually.
However, a report released to RNZ under the Official Information Act showed the council estimated just 10 on-site of buildings in the three-and-a-half years between March 2012 and August 2015.
RNZ sought reports on four councils after the ministry's overarching review found two-thirds had big gaps in how they policed the building safety systems.
Read the full reports here or scroll to the end
For some time, the ministry's repeated response to requests had been only that there was "room for improvement".
Porirua was also not the council with the worst record: 15 out of 38 councils reviewed since 2014 had done no on-site audits, or very few; for instance, three on-site reviews since 2012 out of a stock of 423 buildings. RNZ will be seeking more detailed reports about these councils.
Like many other councils Porirua had some woeful paperwork, with up-to-date compliance schedules on just 25 of its buildings. Those with outdated ones included churches, a kōhanga reo and the council's own buildings.
All the schedules were meant to have been updated by 2013.
The council had also issued just one infringement notice to a building owner in eight years.
It did not know how many Notices to Fix it had issued - these are often used to encourage compliance so that an infringement notice is not needed - but Porirua’s outdated IT system remains unable to record these.
This is despite the ministry saying a Notice to Fix should be seen as a "common everyday building control tool”.
The council told RNZ it had employed someone to look after building warrants of fitness and fixed its building forms since the 2015 review.
"We have addressed all the matters raised by MBIE," council manager of building compliance Kelvin Newman told RNZ in a statement.
"We have a programme in place to complete the recommended 110 onsite BWOF checks by the end of the year," Mr Newman said.
"So far we have carried out 22 [on-site inspections] ... and 70 desktop surveys."
Desktop surveys would not reveal if independent building inspectors were making mistakes or cutting corners, however.
The council also would not say how many on-site audits were done in 2016 and 2017, saying it had not fixed its IT system and could not track warrant of fitness data.
It also would not say how many buildings had corrected their compliance schedules.
Mr Newman pointed out responsibility for keeping a building safe falls on building owners, not councils.
"Building owners who fail to meet these requirements may be risking the health and/or life safety of the building occupants," the ministry said.
Despite the council's failings, the OIA response revealed the ministry took a lighthanded approach. It made some suggestions, but did not go so far as to make recommendations.
"We trust you have found the review to be of some value and have seen it as an opportunity to improve some of your building control activities," the report said.
The reviewers did schedule an earlier-than-usual return visit.
Along with the report on Porirua, three others were released to RNZ.
Wellington City Council and Whangarei District Council had robust building WOF systems, with many checks.
RNZ is seeking more information about the fourth report, of New Plymouth District Council, which the ministry praised despite it having done few on-site audits and issuing zero infringement notices in a decade.