Two strong earthquakes struck in the lower North Island within about half-an-hour of each other last night, along with a series of smaller tremors.
The first, a 4.8 quake at 10.58pm, had its epicentre at Cape Palliser, the island's southernmost tip, about 45km from Martinborough.
It was followed at 11.30pm by a shallow 4.5 quake south-west of Wellington.
Thousands of people have reported feeling the quakes.
A series of weaker quakes were also recorded, including a 2.8 shake 20km north-west of Gisborne, a 2.8 near Taupo at 10.59pm, and a 3.4 tremor at 11.15pm centred 50km south-west of Martinborough.
GNS duty seismologist Carolyn Little said 10 quakes, ranging from magnitude 1.6 to 4.8, hit overnight in a "flurry of activity".
"These are in the aftershock region of the Kaikōura quake," she told Morning Report.
"It definitely won't be the last aftershock we have from that and it won't be the last one that will wake us up."
Two "weak" quakes were recorded in the South Island, a 2.7 near Culverdon at 12.30am and a 2.3 near Seddon at 3.37am.