New Zealand homeowners get satellite land movement reports

Avant has launched LandSure, a service that lets New Zealand homeowners and buyers order satellite-based ground movement reports for individual properties. It opens access to land movement records that have largely been used by councils and engineers.

The Whangārei company says the reports draw on up to 10 years of InSAR measurements and present the findings in plain English. A report costs $345 for a section of up to 500 square metres, while a free address check shows whether a property has measurement points before a purchase is made.

The launch comes as landslide damage claims have risen sharply. The Natural Hazards Commission received almost 13,000 claims for landslide damage in the five years to May 2026, compared with about 3,000 in the previous five-year period, the company says.

Cyclone Gabrielle heightened concern about slope stability and land risk after triggering more than 140,000 landslides in 2023. The Ministry for the Environment has also said climate change can worsen landslides and erosion.

Until now, obtaining measured ground movement records for a single home usually required specialist work, a step many owners did not take unless clear signs of damage had already appeared. Buyers have also faced time pressure during property transactions, limiting their ability to commission technical assessments before offer deadlines.

LandSure is intended as an initial source of information for homeowners, buyers and others making decisions about purchases, subdivisions, extensions or second storeys. It does not seek to explain the cause of any movement. Instead, it shows what has been measured so a geotechnical engineer or other specialist can investigate further if needed.

Avant developed the service after seeing damage to homes in Northland and finding that owners had no direct way to access measured data for discussions with engineers or insurers.

"New Zealanders are inclined to live with a sticking door or cracked driveway rather than pay for an investigation, but small problems can become expensive if left unchecked," said Josh McKenty, Founder and Managing Director of Avant.

How it works

Each report combines satellite radar measurements with public records about a property's land. The measurements come from the European Union's Copernicus Sentinel-1 satellites and are processed by SatSense, a UK company that developed a national ground movement dataset for New Zealand with GNS Science, now part of Earth Sciences New Zealand.

Avant is delivering the reports in partnership with SatSense and Earth Sciences New Zealand. The underlying technique, InSAR, uses repeated satellite radar observations to detect changes in the position of fixed points on the ground over time.

SatSense says its dataset can measure a point's average rate of movement to an accuracy of about 1mm a year. The system tracks hard surfaces such as roofs and paving, which means some properties will not have measurement points available.

That constraint is central to how the service is being offered to the public. Prospective users can check an address first to see whether usable points are present before paying for a report.

Public access

The launch marks a shift in access to this type of information. Ground movement datasets have been available to public bodies, engineers and specialist consultants for years, but access to single-property reports has been limited for homeowners and buyers.

For the property market, that could mean purchasers can review measured movement data earlier in the buying process rather than waiting for a formal technical review. For existing owners, it may provide a basis for deciding whether visible signs such as cracks or misaligned doors warrant further investigation.

Dr Matthew Bray of SatSense said New Zealand is a suitable market for wider use of the data because of its active terrain.

"New Zealand has some of the most dynamic ground in the world, which makes it an ideal place to show what this technology can do. LandSure has taken a dataset built for specialists and made it genuinely useful to homeowners and buyers," said Dr Matthew Bray, Chief Executive Officer of SatSense.

A second executive at the company said the aim was to make the data easier for non-specialists to understand.

"People don't need to be experts in satellite radar to benefit from it. What they need is a clear picture of whether their property or the ground beneath it has been moving, and a sensible next step if it has," said Scoular.

McKenty said the reports should be treated as a starting point rather than a substitute for technical advice.

"The report does not replace a geotechnical engineer. It gives an owner or buyer an accessible first look at what is happening so, if there is an issue, they can engage an engineer to determine why," he said.