The 9.21pm quake was centred near the small township of Methven, about 100km west of Christchurch, at a depth of 5km.
GeoNet said it may have been felt in Akaroa, Amberley, Arthur’s Pass, Ashburton, Christchurch, Culverden, Fairlie, Geraldine, Greymouth, Hokitika, Methven, Mount Cook, Oxford, Timaru, Twizel, Waimate, and surrounding localities.
“That was a rumbly one! Chandeliers swinging here.... about 10km inland from us here in Mount Somers,” one texter told Newstalk ZB.
“Good lot of rolling and a couple of good shudders here in Ross, on the west coast,” another added.
Others said they could feel the shake in Christchurch, Ashburton, Hokitika, and Winchester.
“I am in Timaru just felt the quake quite a good tremor,” said one texter.
Another poster to X, formerly Twitter, said they could feel “minor aftershocks” after the initial jolt.
Dr Jonathan Hanson, seismologist at GNS Science, told Morning Report it was not expecting significant damage from the quake.
He said people close to the epicentre would have felt a sharp shake but further away it would have been a moderate rolling earthquake.
"It would have given people a good shake," Dr Hanson said.
"People who would have gone to bed early would have felt a good jolt."
Hanson said the aftershock pattern was in keeping with a moderate earthquake with the largest aftershock measuring magnitude 3.
"This is in keeping with what we'd expect from a quake of this magnitude. Aftershocks are a normal occurrence after pretty much any earthquake.
"We'd expect them to tail off over the next few days."
He said the aftershocks help GNS map out which faultline the quake has happened on.
In December, a ‘strong’ magnitude 4.4 earthquake hit the South Island 100km north of Christchurch and was felt across the city.
The earthquake occurred at 9.30am on December 9 and was centred 5km south of Culverden and 12km deep, GeoNet said.
More than 550 people, mostly in Christchurch, told the GeoNet site they felt the quake.
It came about two months after a magnitude-6.2km quake hit Geraldine south of Christchurch in what was the strongest earthquake to hit New Zealand last year.
More than 14,000 people posted reports on GeoNet saying they felt that September 20 quake .
It was described as a long, rumbling quake and didn’t cause any violent jolts.
It was the first decent shake to be felt in Canterbury — a region devastated by the 2010-11 earthquake sequence — for some time.
The magnitude-6.3 quake of February 22, 2011, killed 185 people and caused widespread damage to Christchurch’s CBD and many suburbs.
-With RNZ, NZ Herald and Star News