From today, builders will have to provide customers with written contracts and a list of their relevant skills and experience before they start work.
A new house goes up near Wellington Photo: RNZ
The change applies to jobs worth more than $30,000, and those flouting the new rules face fines of $500.
Builders must hand over a contract with specific details of warranties and insurance, a list of their qualifications and advice on how customers should manage the project.
Building and Housing Minister Nick Smith said the new rules would improve the way building work was done, at a time of unprecedented activity.
The measures would hurt only the cowboys of the industry, who were more interested in making money than doing a good job.
"Whenever you've got an industry in boom mode, there's a greater risk of cowboys entering the industry," Dr Smith said.
"Our hope, with these new regulations, is that it is going to keep the cowboys out while still enabling the industry to expand."
The more stringent rules would improve the way building work was done, with more than 25,000 new houses set to be built this year, he said.
The Government expected the changes would lead to fewer complaints in the long run.
