A building industry watchdog is concerned the pressure of Auckland's housing boom, is lowering build quality across the city.
Auckland Council's building control team, says materials are increasingly being substituted for cheaper products to get the job done faster.
General manager of Auckland Council's Building Control Ian McCormick says inspectors are seeing more material substitutions than ever before.
"The boom has attracted a few cowboys trying to cut corners and some importers trying to bring in cheap, substandard products," he says.
Home Owners and Buyers Association CEO Roger Levie told Radiolive's First at Five he is concerned about the magnitude of the problem.
"It's not just leaky buildings but we are also seeing a lot of issues and other issues arising in properties and we suspect that we will be continuing to see that going on and on."
The Council is urging homebuyers to be wary of the situation and for builders to keep customers in mind.
There are concerns this could lead to another leaky building crisis, as the pressure to build fast mounts.
"The quality of construction is not good. A lot of people say to us 'have we solved the leaking building problem' and we really haven't. It's a case of just general defective buildings and poor workmanship that we are seeing."
Mr Levie says sub-standard building materials and time pressured contracts are to blame.
"We are seeing a lot of people who, because of the cost of building, who are looking to cut corners and employ some less than capable builders undertaking working without proper building consent."
Mr McCormick says people need to be vigilant about offers that seem too good to be true.
He says he recently learnt of someone who was cold calling building sites and offering an imported roofing product at 40 percent of the original cost.
In situations like that, Mr McCormick says it is highly likely the product would not comply with New Zealand building standards.
The council is urging builders to save themselves and their customers thousands of dollars by seeking the proper sign-off before using substitute building products.