Widespread weaknesses in quality control standards for construction could put people at risk, warns the building industry.
A quick survey of three specialist building trades in this country found 11 standards were confusing, outdated or had been dropped entirely.
The Specialist Trade Contractors Federation, which surveyed its members, called the confusion the "tip of the iceberg" and called on the government to take action.
Roofing Association chief executive Graham Moor said some standards were not very clear, and there was an absence of standards in some areas.
"So we've got a fire code which says how these things should perform but where are the standards that back it up?
"You've actually got people confused - 'which do I follow, where's the bar as to which product I should use where?'"
Mr Moor said an example was clear roof sheets, which came in four grades, from fire resistant to combustible.
Suppliers surveyed reported seeing building plans that were not clear about which grade to use and caused confusion among installers.
"You might use it on a veranda at a school, for example," Mr Moor said. "The last thing you want is your children exiting because there's a fire in the classroom, and the veranda roofing catches fire and drops molten product on top of them."
Mr Moor said intense competition to win contracts was putting a squeeze on prices, forcing tradespeople to use cheap products.
"This is really scary - you won't know until such time as you have a fire if you've got the right product on the roof."
The survey found standards were viewed as good in the field of fire protection, but there was concern they needed updating, particularly the standards for alarms in commercial and industrial buildings, which were now seven years old, and handheld fire extinguishers, which had not been updated in 12 years.
Argus, one of the country's biggest fire protection contractors, said there was little money to modernise the standards.
"What it means on the ground is that there could be technologies around sound and detection and maybe wireless technology, where technologies internationally are available but we are not necessarily easily able to use them in New Zealand because the standard doesn't reflect those technologies," said general manager Jacqui Bensemann.
"In fact, in some situations, our standard references some standards that are now obsolete."
That has forced the standards committee to provide interpretations on a case-by-case basis, which soaks up time and money.
Fire equipment manufacturers will be meeting in Wellington tomorrow to discuss imposing a new levy on fire alarms, which would be used to upgrade standards, as happened with sprinkler systems.
It can cost hundreds of thousands of dollars to update a standard, and it must be completely funded by users.
A proposed joint scaffolding standard with Australia was dropped in New Zealand after industry players refused to pay up.
Industry feedback has indicated things have got worse since the Ministry of Business, Innovation and Employment took over Standards New Zealand 15 months ago. The ministry did not respond.
But a ministry email said of the scaffolding standards: "It appears we did not consult with stakeholders to gauge interest and secure the commissioning fee in order for NZ to participate [with Australia]. Unfortunately without a firm commitment to funding, NZ will not be able to participate in these projects."