The Ministry of Business, Innovation and Employment (MBIE) is concerned about dodgy plumbing fittings being sold by small-scale importers.
MBIE says it appears some importers don't understand their obligations, but as yet the scale of the problem and availability of the products isn't known.
MBIE is planning a major educational campaign this year to promote the need for building products to have evidence of compliance to New Zealand standards.
However, a major importer of plumbing pipe into New Zealand says the Government needs to set up an investigation unit to clamp down on sub-standard fittings.
Milton Sands from Aquatherm says Australia has a compulsory standards regime called WaterMark, but in New Zealand standards are voluntary, and no one knows how big the problem is.
"Until somebody actually goes and test things like WaterMark in Australia, until we have somebody like that in New Zealand, it is unknown."
Mr Sands says a lot of product is coming in from China and India because of the prices, and those countries don't have the regulations that we do.
"To get WaterMark in Australia you have to have them look into your product; they will go to your factory, they will take samples and they will test, they will do surprise testing throughout the year and they make sure your product is what it is meant to be."