Warnings about substandard building products coming into the country have triggered a major industry inquiry.
The Building Industry Federation and Construction Industry Council are looking into product quality after fielding a flood of calls from worried members about a wide range of untested imports.
The inquiry follows news of an investigation by the Ministry of Business, Innovation and Employment (MBIE) into a "grey market" in plumbing products that might breach standards.
Building Industry Federation chief executive Bruce Kohn said the problem was escalating.
"The federation has received many expressions of concern about the questionable quality of a range of new products and materials entering the country," he said.
"That's especially so in the areas of plumbing, electrical products, exterior claddings, roofing, glass and power tools."
There were also problems with fake certifications and appraisals in the building industry, he said.
An example was a council inspector checking pipes running to a new house, which were meant to be able to bear a person's weight.
"The inspector jumped onto the piping in the trench and it just gave way.
"He did it again further down the trench and the same thing happened. We then found out that the builder concerned had been importing this pipe from China and obviously it was of very questionable quality."
Minister: No evidence of problems
Minister of Building and Housing Nick Smith said his officials had found no evidence of problems with substandard plumbing products in new homes.
Plumbing groups had said there were no legally enforceable standards for pipes and fittings in New Zealand, and half of all new houses had plumbing that would fail performance tests in Australia.
The groups said there should be compulsory certification of building supplies, as in Australia.
But Dr Smith dismissed claims the country could be heading towards another 'leaky homes'-type crisis caused by defective plumbing fittings.
The ministry had made inquiries but found no major problems, he said, and advised anyone with evidence of poor-quality plumbing products to talk to the government.
In a separate interview today, Dr Smith told Morning Report plumbers were responsible for deciding whether the products they installed met New Zealand standards.
"Every single piece of plumbing work has been certified by a plumber, and if that work is found - two, three or five years hence - to be substandard, that plumber is in the gun and potentially has his registration up for loss if he has not met those Building Code requirements."
The public should be wary of claims about substandard foreign products, because it could just be local companies trying to reduce competition from overseas, he said.
The Building Code demands that hard-to-replace products last at least 50 years, while those a bit easier to replace should last five or 15 years.