There's no mandatory government licence for private pre purchase building inspectors in New Zealand. Anyone can legally offer the service. Which means who you pick matters as much as what they find.

NZS 4306:2005 is the standard that exists anyway. It sets out scope, method and reporting. It isn't legally required, but the Disputes Tribunal measures reports against it. Ask whether they work to it.

Then:

Professional indemnity insurance, and how much. An inspector with no cover has nothing behind them if they miss something significant.

A sample report. Not a summary, the actual document. Photos? Moisture readings? Does it list what couldn't be accessed? Does it tell you what needs a specialist? A twelve-page report and a sixty-page report don't do the same job.

Industry body membership. Building inspectors and building surveyors each have professional organisations with their own membership requirements and standards. While membership can demonstrate a commitment to professional development, it is not a prerequisite for competence. A BCITO-trained, trade-qualified building inspector may be just as capable and experienced as a member of any industry body.

Whether they hold an LBP licence and what that covers. The Licensed Building Practitioners scheme is for people who do or supervise restricted building work. It is not a licence to inspect. An inspector who holds one has building knowledge, but it isn't a qualification to inspect.

Who turns up on the day. Some firms subcontract. Ask who's coming and what experience they have with that construction type, especially with plaster cladding.

What's excluded, in writing. Roof space, subfloor, outbuildings, the LIM, which they don't do anyway.

The liability clause. Every report limits liability somehow. Read it; it tells you what recourse you've actually got.

On price, a standard report sits in the hundreds and specialists cost more. The gap between a cheap inspection and a thorough one is small next to what a missed defect costs.