Source: Auckland Council
Landslides impact homes, infrastructure, roads and services and the effects of climate change can exacerbate these risks over time. The devastating landslides in and near Mauao, Mount Maunganui, are another stark reminder of the risk of landslides to life and property.
In Auckland, we have seen these impacts on a significant scale – from the estimated 50,000 landslides that occurred during the severe weather events of early 2023, the Auckland Anniversary Weekend floods and Cyclone Gabrielle.
Councillor Richard Hills, Chair of the Policy, Planning and Development Committee, reiterates the importance of understanding the natural hazards in our region, including landslides, and cautions against the spread of misinformation.
“Landslides can have a serious impact, and we’ve seen this in our region and across the country. Landslides had devastating effects in both the 2023 Auckland Anniversary floods and Cyclone Gabrielle on both private and public land. This included loss of life, and hundreds of millions of dollars of damage to property,” says Cr Hills.
“Often stable land with no history of slips can quickly change to a landslide when the soil is saturated or during a torrential rain event. Climate change can be a factor in making these impacts more extreme.
“The council has invested heavily in research and tools to improve how we understand and assess landslide risk and arm Aucklanders with information. It’s really important that we look to trusted sources of information during these times rather than listen or spread misinformation.”
What is a landslide?
A landslide is the movement of a mass of rock, debris or earth (soil) down a slope.
Landslides across the Auckland region impact homes, infrastructure, roads and services and they typically occur:
- On steep slopes (natural or modified)
- On slopes comprising weak materials
- Due to stream or sea erosion
- Due to failure of structures like retaining walls.
Landslides can be triggered by:
- Heavy or prolonged rainfall, which may become more severe and frequent due to climate change
- Earthworks, where a landslide can be triggered by the weight of material added to a slope, or by loss of support where material is dug out below a slope
- Strong earthquake shaking.
Landslides can happen without warning
Heavy rain can cause landslides, even after the rain has stopped. If you feel an immediate threat to your life or property – call 111.
Stay alert and look out for the warning signs. You’ll need to act quickly if you see them:
- Rumbling or cracking noises that sound like falling trees
- Small landslides or rock falls at the bottom of slopes and sinking land at the top of slopes
- Sticking doors and window frames, which may mean the land is slowly moving under the building
- Gaps where window frames are not fitting properly
- Steps, decks, and verandas, moving or tilting away from the rest of the building
- New cracks or bulges on the ground, road, footpath, retaining walls and other hard surfaces
- Tilting trees, retaining walls, or fences
- New springs (water seeping out of the ground).
Get out of the path of the landslide quickly. Evacuate if the building you are in is in danger.
Once you have made sure that you and other people are safe:
- Alert emergency services (if you haven’t already) – call 111
- Call Auckland Council on 09 301 0101 from a safe location
- Report broken utilities (water, gas, electricity) to the appropriate companies
- Stay away until authorities give the all-clear, as further damage is likely – landslides can happen progressively, often days after a triggering event
- Record the landslide details using the landslide reporting tool.
Enhancing our understanding of landslides in Auckland
In 2025, Auckland Council completed a region-wide study to map landslide susceptibility, to help Aucklanders understand and avoid these risks. This work means we are better informed on the potential for landslides in the region and helps us plan better for the future.
Landslide susceptibility identifies areas that may be more prone to landslides. It does not predict landslides or their impacts but helps guide planning and builds a better understanding of where landslides are more likely.
It’s important to understand that these maps do not describe hazard or risk. This means that they do not show how many, or how often, landslides will occur (the hazard), or what the consequences could be (the risk). But rather, it helps in our planning and understanding of landslides.
Auckland Council Chief Engineer Ross Roberts explains that the maps were prepared using regional data and, although they are not property specific, provide valuable insight into landslide risk.
“These maps provide vital information to planners, infrastructure authorities, owners, developers, and engineers so that they can understand and manage the risks from landslides,” says Ross.
“However, as detailed, site-specific information is not available across the region, the maps can’t include some site-specific conditions and features – a reality when dealing with granularity and dynamic information. This means detailed assessments may still be required to accurately determine risk for an individual property. Landslide risk assessments completed as part of the response to the severe weather events of 2023 are an example of a method we have used to provide more detailed risk information.”
Using the new data in Auckland’s planning rules
Auckland Council introduced stronger planning rules to respond to natural hazards, including landslides, in November 2025.
Introduced as part of Plan Change 120, Auckland’s landslide susceptibility maps are now used to assess risk when considering resource consent applications in areas that could be prone to landslides.
The new maps give the council a clearer and more reliable view of where the risk may be. Resource consent applications for activities in these areas can be carefully considered and amended as needed to help manage these risks.
Any resource consent application for work in an area subject to natural hazards, like landslides, flooding or coastal erosion, needs a risk assessment. This helps make sure new buildings and activities can withstand long-term risks.
How to reduce your risk
“It’s important for landowners to be aware that insurance is unlikely to cover the full costs of repairing damaged land. It’s much cheaper – and safer – to prevent the landslide occurring in the first place,” says Ross.
Landowners can reduce the risk of landslides, and checking vegetation or thinking about your gardening is a great starting point.
“Plants can be very effective at improving the stability by sucking the excess moisture out of a slope, and by reinforcing the slope with their roots. Trees can also add stability, and slow surface erosion. However, they can also be a cause of landslides if they are unstable, so it’s worth getting an arborist to check on large or old trees on slopes. The type of plant is also important – for example, pōhutukawa can be quite effective, but pines are generally less stable, and their shallow roots do less to reinforce the slope,” says Ross.
Managing stormwater can also make a big difference. Check where the stormwater from your roof flows – it shouldn’t go onto steep or unstable slopes.
Make sure that you know where overland flows from areas uphill of your house go, and that those overland flow paths aren’t blocked.
You can visit Auckland Council’s Flood Viewer website to check overland flow paths in and around your home, as well as make changes to your home to reduce the risk of flooding.
LiveNews: https://nz.mil-osi.com/2026/02/05/understanding-landslides-what-you-should-know/
