New guidance published on Monday by the Real Estate Authority requires salespeople to disclose methamphetamine contamination beyond 15 micrograms per 100 square centimetres as a property defect, RNZ reports.

Real Estate Authority Chief Executive Belinda Moffat said the rules aim to protect buyers and provide clarity, noting that the authority has handled 12 methamphetamine-related matters in the last 3 years, RNZ business (NZ) reports.