The quake hit at 3:36 pm with its epicentre about 66 kilometres (41 miles) from the South Island town of Kaikoura at a depth of 55 kilometres, the US Geological Survey said.
The local GeoNet monitoring service measured the quake at 6.2 and said it was felt across the entire country, but was unlikely to cause damage because it was so deep.
“I am advised that MCDEM (emergency management) hasn’t received any reports of major injuries or damage,” Civil Defence Minister Nikki Kaye said.
However, there were widespread outages on landline and mobile networks, while some rail services were briefly suspended as tracks were inspected for damage.
Kaikoura District Council chief executive Stuart Grant told TVNZ the quake felt like two tremors in quick succession, describing the second as a “big jolt”.
He said the council building was evacuated as a precaution but appeared undamaged.
The manager of Kaikoura’s Mitre 10 hardware store James Hills said the quake dislodged items from shelves and sent panicked customers fleeing from the building.
“(There was a) fair bit of panic… everything was falling off the shelves,” he said.
“There’s been a little bit of damage, certainly not heaps, but yeah, there’s a lot of stuff fallen over.”
Local resident Caleb McNabb said on Twitter that buildings “swayed” in Kaikoura’s main street, while Wellington’s Mandy Simpson tweeted “that was a long, horrid shake”.
The quake struck in the same region as a 4.7 tremor on Thursday that jolted office buildings in Wellington.
There were also two 6.5-magnitude quakes around the same area in July and August 2013. GeoNet data manager Kevin Fenaughty said it was unclear if there was a direct relationship.
“We cannot be certain that it hasn’t been triggered by stresses from all those quakes over time,” he said.
A devastating tremor hit the South Island city of Christchurch in February 2011, killing 185 people.
New Zealand is on the boundary of the Australian and Pacific tectonic plates, which form part of the “Ring of Fire”, and experiences up to 15,000 tremors a year. (AFP)