A magnitude 5.5 quake has hit near Seddon, shaking the middle of the country including the capital Wellington.
The quake hit at 3:34pm at a depth of 17km, 35km southeast of the South Island settlement.
At 4:00pm a magnitude 4.7 aftershock hit at a depth 15km, 35km east of Seddon.
Thousands of people have reported feeling the quakes.
One resident at a camp site in Picton said there was no warning before the quake hit.
"It just started bouncing," he told RadioLIVE.
"I was just sitting here having a beer and even my dog's jumped out of bed."
Tom Jackson was in his Wellington apartment *during the earthquake* and said "it was pretty big, it rocked a lot, there was a crunching sound at the start".
"It was enough to remind me of what happened previously and I guess it was a case of I hope this doesn't get any bigger and do what it did last time".
Fire, police and ambulance services said they had not received any callouts immediately after the quake, and a Wellington airport spokesperson said the airport is operating as normal.
A Wellington City Council spokesperson said at this stage there have been no reports of damage.
The spokesperson said that owners of buildings that had been impacted by the November magnitude 7.8 earthquake should check to see if there has been any further damage.