The Government is being warned a spike in non-compliant windows and doors could spark another leaky building crisis.

The Window and Glass Association has written to Building Minister Chris Penk requesting urgent action to address the issue.

In a letter shared with Newstalk ZB, it warns the problem is being compounded by the increasing incidence of manipulated or false compliance documentation used to pass off substandard window products as compliant to councils and builders.

The association believes most non-compliant windows seem to be either imported or locally built using imported systems and unskilled labour.

It’s asking Penk to direct MBIE to strengthen its enforcement capability and activities, significantly tighten its certification audits, and ensure New Zealand’s building regulations are robustly enforced.

Association chief executive Brett Francis said they had already identified around 20 suppliers in Auckland who are selling non-compliant product.

He said many homeowners, builders and councils carry the risk when building products fail, even though it’s expected the compliance was verified.

“This can lead to not only safety risks but also significant financial losses through costly remediation work down the line.”

Francis said there was no authority enforcing the rules.

“It’s incredibly frustrating for us, but it’s more concerning for these homeowners who’ve spent a lot of money.”

NZWindows Director Kevin Allum said he estimates around one in ten products have questionable compliance, and in Auckland about 15% of products are questionable.

He said it’s easy to put a sticker and a stamp on something, and when the building inspectors see that, they assume it’s compliant.

“It’ll look like a New Zealand number, but they’ll just put a letter in the wrong place on the logo, so for any layperson at all it’s almost impossible to detect.”

Allum said people shouldn’t be so focused on getting a cheap product.

“For 1.7% of your home, do you really want to jeopardize the safety and weather tightness of your home?"

McKechnie Aluminium and Omega Windows Managing Director Dave Slomp said practices just keep getting worse, and every supplier they investigate turns up a new way of defrauding builders and homeowners.

“They’re manufactured with fake window stickers, fake test certificate, and when we pull them to pieces we find some of the basic principles of window manufacturing haven’t been followed.”

Slomp said the new Overseas Building Products Bill is making it a lot easier for the dodgy product to come through.

“It feels like Auckland is an experiment of deregulation in the industry and the results are leaking into people’s homes.”

New Zealand is a long, narrow island country, and had high window and door standards for a reason, Slomp said.

“It feels to me we are potentially sleepwalking our way to the next leaky building scandal."

Building and Construction Minister Chris Penk said he is aware of concerns about the risk of non-compliant or fraudulently certified window products in the market.

He said MBIE has begun proactive analysis of manufacturers, retailers, and importers of glass windows and doors across New Zealand in relation to the Building Products Information Requirements.

“MBIE has already reviewed several window products within the building industry, including some that did not meet BPIR requirements.”

Penk said he’s spoken with the Window and Glass Association and intends to meet with them soon to discuss this issue in greater depth.

He said he’d like to clarify the 20 companies the Association identified selling non-compliant windows were doing this before the Overseas Building Products Bill came into effect.

“From my discussion with the Association, I understand they believe these companies were operating in this manner before the legislation came into effect. It’s important to clarify that the allegation is not that this issue arose because of the legislation.”