A magnitude 6.3 earthquake has struck off the Kāpiti Coast, Geonet says.
The quake struck at 7.38pm 50km north-west of Paraparaumu at a depth of 50km, with strong shaking, Geonet's report on the quake said. Its preliminary reports had measured the quake at 6.1 magnitude.
GeoNet seismic duty officer Jen Andrews said it was a "slab event" - meaning it was located in the tectonic plate that goes down under the North Island.
That also meant aftershocks.
"So we will be expecting to record aftershocks ... probably the largest would be one unit smaller, so magnitude 5. And potentially we will have some of those larger aftershocks because this event was quite deep.
"It's about 50 kilometres deep, give or take, so that means it happened ... probably as a slab event. So what people need to know is that it was felt quite widely and strong. We've had about 50,000 felt reports over the North Island and South Island."
There was no tsunami threat, despite the quake feeling 'long and strong' for many people, Andrews said.
People could expect to feel aftershocks the coming hours - and even days - and should drop, cover and hold when they did, she said.
People as far away as Southland and Northland reported feeling the quake.
RNZ staff in Wellington said the office was hit by a "solid and long rumble that went on for a fair bit. Nothing knocked over though" and "a good shake that lasted a surprisingly long time".
Family members of RNZ staff reported feeling the earthquake from a number of regions.
In Porirua, 20 minutes from where Geonet says the quake hit, one said it "started with a bang and then a strong shake". In Palmerston North, a table in someone's hallway was knocked over and the TV almost fell.
"On Paraparaumu Beach it started smallish but noticeable, and it was pretty creaky," one reporter said. "Here on the beach, quakes have this awful sickening roll that goes on for ages, almost like when you've been on the sea for a few hours and then later when you're on land you still feel like you're rocking around."
A reporter near Kāpiti said her house "rattled and rolled and you could hear all the beams being shaken about through the frame".
"It felt like sharp uneven waves were running through the building from one end to the other.
"We got under a door frame quite quickly and then it kept getting bigger. We were worried it was a landslide with all the rain, as we're on a clay slope so the first thing we did was get out of the building and checked the slope - not a nice feeling, and we could hear one of the neighbours swearing.
"We had no damage, but we're about 60km from where GeoNet initially placed it near Kāpiti, so we're really hoping everyone close to the centre is okay - that was a big shake."