A severe magnitude 6.5 earthquake, which hit central New Zealand this evening, was not the last, but scientists say it will hopefully be the biggest.
GeoNet said it was centred in the Cook Strait, 20 kilometres east of Seddon at a depth of 17 kilometres. It struck at 5.09pm.
The Pacific Tsunami Center in Hawaii said the quake did not generate a tsunami.
The 6.5 magnitude quake was likely linked to a fault in the Cook Strait capable of generating far more severe shaking, GNS Science said.
Dr Kelvin Berryman, GNS Science director of Natural Hazards, said the severe shaking over the past three days was probably linked to one of several faults capable of generating shakes of magnitude 7.0 or more.
The most likely candidate was the Needle fault, although the location of the series quakes over the past three days did not quite match up.
He said a larger quake was unlikely but the swarm that kicked off on Friday morning was not following the normal aftershock pattern, in which the tremors became progressively less severe.
This afternoon's 6.5 magnitude shake, the biggest in the latest swarm, meant the shaking was not following the usual pattern, he said.
GNS should have a clearer idea of the probability of another big, or even bigger, quake by tomorrow, he said.
A spokesman for Civil Defence Minister Nikki Kaye confirmed a civil defence emergency had not been declared, but an emergency centre had been set up in Thorndon.
