Random New Zealand Address Generator

Software testing, form validation, and database seeding require structurally valid address data that matches real-world formatting conventions. Using malformed test addresses causes silent failures in geocoding pipelines, postcode-based shipping calculators, and address parsing libraries. This generator produces addresses conforming to New Zealand Post's addressing standard: unit/flat prefix, street number, street name with suffix, suburb, city, region, and a 4-digit postcode. Each postcode is mapped to its correct geographic region to prevent logically impossible combinations such as a Wellington postcode paired with an Auckland suburb.

The generator draws from a curated dataset of over 200 real NZ street names, 16 regions, and 80+ suburb-city-postcode mappings. Street numbers follow realistic distributions weighted toward lower ranges. Unit numbers appear on approximately 15% of generated addresses. All output is fictitious - no generated address is guaranteed to correspond to an actual property. For privacy-sensitive testing, this is the correct approach: real addresses in test datasets create GDPR and NZ Privacy Act 2020 compliance risks.

Each address is assembled from independently randomized components constrained by geographic consistency rules. The generation pipeline follows this structure:

Where Unit is optionally prepended with probability P_unit = 0.15. Street numbers are sampled from a weighted distribution:

This produces a natural distribution skewed toward lower house numbers, matching real-world addressing patterns. The geographic constraint function validates that lookup(Postcode) = Region, ensuring no logically invalid pairings. Street suffixes are drawn from a set S = {Street, Road, Avenue, Drive, Place, Crescent, Terrace, Lane, Way, Close, Heights, Parade, Grove, Court, Rise} with uniform probability.