Gisborne is a remote city on the northeast North Island of New Zealand, close to the Hikurangi Subduction Zone, subject to a range of geohazards. These primarily include tsunami, earthquakes, coastal erosion, flooding, mud volcanoes, and landslides. The city is remote from other urban centres, taking >3 hours to reach the nearest adjacent city via rural roads that are vulnerable to closure during and following natural hazard events. In particular, landslide risk in recent years has been exacerbated by urban and suburban expansion of residential development into erosion-prone steep hillslopes surrounding the city. The hills are underlain by weak Neogene sediments and uplifted Pleistocene estuarine deposits. Sentinel-1 InSAR has revealed the pattern of slope deformation across Gisborne’s steepland periphery from January 2016 to December 2021. Velocities in the line of sight were obtained from the stack of interferograms and projected along the direction of maximum slope, to extract the true displacement on the slopes. The ascending and descending data sets were combined to reveal the vertical and horizontal components of the deformation. Site investigations have revealed that the soils are smectite-rich and exhibit expansivity. In addition, small amounts of the toxic “asbestiform” mineral, erionite, have been detected in soil exposures in landslide scarplets. The erionite formed within altered volcanic ash, but the exposure risk is probably mitigated naturally by vegetation cover and rainfall. Slope deformation time series data was also compared with rainfall to identify seasonal changes, as well as shrink/swell of expansive soils. Despite clear evidence of the effects of tree removal, loading of slopes by construction activity, slope cutting, and installation of unconsented, inadequate retaining walls contributing to landslides, such activities continue to occur.