Consents for alterations are also down on last year, with 425 at an average value of $36,748, down from 474 at an average value of $29,367.
Carterton builder Scott Coulson, of Coulson Family Homes, said the law was a useful safeguard for builders as well as clients.
He mostly carried out full builds and already abided by the requirements.
"It's just something I do without saying," he said.
"There's a little bit of responsibility on the client too from the point of view of doing their homework on someone."
Good communication between builders and their customers was key, he said.
"Anything in life whether you're building a home, or whether it's [a situation] with your partner, it's just about communication, because if people don't talk then things get mixed up in bits and pieces."
Dr Smith said the new requirements would reinforce the good practice of many building repairers while "constraining cowboys only interested in making a quick buck".
"We need to improve how building work is contracted in New Zealand to ensure better quality work, improved affordability and fewer disputes.
"We need to replace a 'she'll be right' with a 'doing it right' culture, with increased professionalism, open disclosure and clear expectations about what work is to be done, at what price and in what timeframe."
The legislation is part of a wider programme of regulations introduced in the wake of the leaky buildings problem and the Canterbury earthquakes.