Residents in Wellington may have witnessed a luminous phenomenon known as earthquake lights on Monday morning.
Instagram user Syrian Kiwi, based in Wellington, posted a video showing the lights flashing in the sky.
"Sky during earthquake in Wellington. Hope everyone's safe," they wrote.
Other videos posted to social media showed the same phenomenon. Cameras at Napier Port also captured the electrical charge.
Earthquake lights tend to occur around continental rifts, where vertical faults allow stress-induced electrical currents to flow rapidly to the surface, producing the phenomenon.
The lights are similar to auroras and produce a white and blue combination of colours.
They generally only appear when earthquakes have a magnitude 5.0 or higher.
Experts say the lights may one day help predict the approach of future earthquakes.
Similar lights were seen after the Canterbury earthquake in September 2010.