The latter half of 2025 has delivered the most significant changes to Auckland’s planning framework since the Unitary Plan first became operative. On 24 September, Auckland Council formally voted to withdraw the controversial Plan Change 78 (PC78) and replace it with Plan Change 120 (PC120): Housing Intensification and Resilience. PC120 was then publicly notified on 3 November 2025.
We have had several weeks to both review the notified version of PC120 and experience Auckland Council’s application of it. This article distills our learnings so far.
On the face of it, the headline story is the shift in zoning philosophy. PC120 moves away from “blanket” intensification via the Medium Density Residential Standards (MDRS) and towards a targeted approach that concentrates density around centres and transit nodes. But for our clients, the most critical changes are in the Natural Hazards chapters.
Whilst the proposed zoning changes are not live, the new rules regarding natural hazards, flooding, and land instability have immediate legal effect. This creates a new operational reality for development in Auckland today.
From Mitigation to Avoidance
The planning regime prior to the notification of PC120 operated largely on a “mitigation” philosophy. If a site had a hazard (such as a floodplain), the solution was engineering. We raised floor levels, bridged over pipes, and engineered retaining walls. If the hazard could be mitigated, the development generally proceeded.
PC120 fundamentally alters this equation by introducing a Risk-Based Framework. This framework assesses risk as a combination of the hazard’s severity and the activity’s sensitivity. It categorises risk into three tiers:
- Acceptable Risk
- Potentially Tolerable Risk
- Significant Risk
The policy directive for Significant Risk is no longer to “mitigate”, it is to Avoid. In the language of the RMA, “avoid” is a powerful directive that leaves little room for negotiation. If a proposal triggers a Significant Risk classification, the pathway to consent becomes exceptionally narrow.
Flooding Depth and Velocity
The definition of a “hazard” has also become far more granular. It is no longer sufficient to identify that a site sits within a floodplain. PC120 introduces strict hydraulic metrics to define a High Flood Hazard Area:
- Water depth exceeding 500mm; or
- A combined Depth x Velocity product exceeding 0.4 m²/s.
Crucially, Auckland Councils Geomaps system often does not display velocity vectors. A site might appear to have manageable ponding, but if that water is moving, it may trigger a “High Hazard” classification. For residential activities (classified as “Sensitive”), being in a High Flood Hazard Area automatically results in a Significant Risk status.
This necessitates a change in due diligence. Reliance on standard Council flood maps or basic LIM reports is now a liability. To prove a site is developable, we are increasingly seeing the need for hydraulic modelling at the pre-purchase or concept stage to accurately calculate depth and velocity.
Coastal Hazards
PC120 also introduces a sophisticated tiered system for coastal environments, moving beyond simple setback lines to complex hazard areas based on timeframes and sea-level rise scenarios. These rules also have immediate legal effect.
The plan identifies specific zones for both Coastal Erosion and Coastal Inundation, split into three tiers (Area 1, 2, and 3) reflecting increasing timeframes and climate change scenarios (e.g., ASCIE – Areas Susceptible to Coastal Instability and/or Erosion).
The implications for waterfront assets are:
- Coastal Hazard Area 1 (Imminent/High Risk): For sensitive activities like residential dwellings, being located in Area 1 triggers a Significant Risk classification. The policy direction is to Avoid. This effectively places a moratorium on new housing in the most exposed coastal fringes.
- Coastal Hazard Area 2 & 3 (Future Risk): In these areas, risk is generally classified as Potentially Tolerable for existing urban areas. However, this does not mean “business as usual.” Development here will require a rigorous Risk Assessment demonstrating that the building is adaptable, relocatable, or that the risk can be managed over a 100-year timeframe without relying on new hard protection structures (seawalls), which are strongly discouraged.
New Requirements Under Proposed Appendix 24
PC120 introduces Appendix 24: Landslide Hazard Risk Assessment Methodology, which also has immediate legal effect.
Previously, a geotechnical report might have relied on qualitative assessments of stability. Appendix 24 mandates a rigorous, often quantitative approach for sites in “High Susceptibility” areas. It requires specific assessments of probability and consequence. For greenfield developments or sites outside existing urban areas, the policy is explicitly to avoid activities that give rise to high landslide risk.
The Cost of Compliance
These changes bring a tangible “Feasibility Crunch.” The cost of the technical reporting required to navigate PC120 is significantly higher than under the operative plan.
- Flood Risk Assessments: A comprehensive flood model to challenge a hazard classification or prove safety can cost between $5,000 and $15,000, and adds weeks to the project timeline.
- Coastal Hazard Assessments: Properties in coastal zones now require detailed assessments of Areas Susceptible to Coastal Instability and Erosion (ASCIE). This often requires specialist coastal engineering input to model 100-year sea-level rise scenarios and design “relocatable” structures, adding significant complexity and cost to waterfront projects.
- Geotechnical Reporting: Compliance with Appendix 24 is likely to push geotechnical investigation costs well beyond the standard $3,000 – $7,000 baseline for a single dwelling, potentially doubling costs for complex sites.
Furthermore, because these rules have immediate legal effect, they apply to resource consents currently being processed by Auckland Council. We are already seeing Auckland Council issue section 92 requests requiring applicants to reassess their designs against the new “Significant Risk” matrices.
Strategic Advice
The window to submit on PC120 closes on 19 December 2025. However, for landowners and developers, the priority is to understand how the “live” rules affect your portfolio now.
- Re-evaluate your constraints: Do not assume that a site with a “Residential” zoning is developable if a hazard applies. The hazard rules act as a gatekeeper.
- Upgrade your data: Desktop feasibility studies must now include hydraulic and geotechnical rigour. The cost of a failed consent application far outweighs the cost of early technical reporting.
- Check the maps: PC120 uses Qualifying Matters to downzone specific lots within broader zones. Use the PC120 Map Viewer to check your specific property.
PC120 represents a necessary correction toward resilience, but it places the burden of proof squarely on the applicant. In this new landscape, technical foresight is the most valuable asset you can have.
