There have been nearly 40 aftershocks after the 6.0-magnitude earthquake in Canterbury on Wednesday.
The most-recent of the 37 aftershocks was just before 1:20pm, GeoNet said in statement.
People from across New Zealand reported feeling the original quake, which struck at 9:25am. GeoNet said it was 11km deep and located 45km north of Geraldine.
"As at 1:28pm, we have located 37 aftershocks following the M6.0 at 9:14am, the largest of which have been an M3.8 at 1:18pm and an M3.6 which occurred at 9:25am."
Civil Defence said the quake did not generate a tsunami risk.
GeoNet recorded the quake as causing "strong" shaking. It said more than 14,000 people reported feeling it.
People as far north as Auckland reported feeling the quake, which was the highest magnitude tremor to strike New Zealand in 2023.
"[The] quake was centered in the Rangitata Gorge area where two identified active faults meet - the Ben McLeod Fault and the Lake Heron Fault. As the magnitude was relatively small for a major fault, it was probably on a subsurface fault between those two known faults.
"This area has no known historical quakes above M5.0. The nearby large faults are estimated, from landform evidence, to have each ruptured several times in the recent geological past (within the last 18,000 years), but not since European records began."
Wednesday's quake was about 70km from the Alpine Fault, GeoNet said.
The quake was originally reported as 5.4-magnitude but was updated several times.
While the Timaru District Council was assessing buildings in the area as a precaution, the National Emergency Management Agency (NEMA) said it had not received any immediate reports of damage.
"That was way too close for comfort! Peel Forest pretty close to epicentre - whole house shook, cupboard doors swung open, flashbacks to the ChCh quakes," former Green Party MP Mojo Mathers said on Twitter.
"Rocked here in Timaru," another person commented on Facebook. "So scared."
'Always pretty cautious'
The Mayor of the Timaru District, where the quake's epicentre was, says it was a "pretty solid rumble".
Nigel Bowen said he hadn't experienced such shaking since the 2010/11 Canterbury earthquakes.
"Geraldine, the township for us that's closest to the centre of the earthquake... everyone's OK at this stage so we got off the hook on this one," he told Newshub.
"I think it's been a good 10 years since we were all aware of a quake... we're well aware of the effect it's had on Canterbury in the past so I think people are always pretty cautious when you get a good shake that you can feel.
"[The] council and Civil Defence is just on alert and I know that other sectors as well as police and FENZ (Fire and Emergency)... will just be watching closely to see what response is needed but hopefully that's it."
The Timaru District Council said it had closed town's Farmers car park as a precaution "while engineers assess the structure".
"After the earthquake this morning there have been no reports of damage and we are checking with our facilities," the council said in a statement.
"Some facilities may be closed in the interim as a precautionary measure.
"Given the nature of the quake it is unlikely there is any damage, but we are taking a safety-first approach."
Other facilities in the Timaru District, where the epicentre of the quake was, were being checked by engineers, the council said.
"This includes but is not limited to Aorangi Stadium, the Farmers carpark, Geraldine Cinema and the lift at the Piazza."
NEMA director John Price said the tremor was a "serious reminder" of New Zealand being an earthquake-prone country.
"And while today's earthquake fortunately didn’t create a tsunami threat, don't forget 'long or strong, get gone,'" he said. "That means if you're near the coast and you experience a long or strong earthquake, don't wait for an official warning. Evacuate immediately - as far inland as possible, or to higher ground.
"This is also a reminder to have a 'prep talk' with your household and for workplaces, schools and marae to make sure they’re earthquake-ready."
The shake comes just weeks after the 13th anniversary of the 2010 Canterbury earthquake.
Homes were destroyed and others left uninhabitable after the magnitude-7.1 hit at 4:34am on September 4, 2010.
It struck south-east of Darfield - about 40km west of Christchurch and around 120km north of Wednesday's quake.
While no-one was killed in the 2010 quake, it sparked many large aftershocks including the devastating 6.3-magnitude Christchurch tremor in 2011, which killed 185 people.
