A 4.8-magnitude undersea earthquake to the north of New Zealand's White Island has been felt by some on the Coromandel Peninsula, but is too small to affect the island's volcano.
The moderate quake struck 110km north of White Island just after 8.30am local time on Thursday, at a depth of 30km, GeoNet says.
About 25 people reported feeling it, saying it felt either weak or light.
There is evidence from around the world that very strong quakes could influence volcanic activity, says GNS duty volcanologist Mike Rosenberg.
But the jury was out as to whether they could trigger eruptions, he told AAP.
Thursday morning's quake was too far away to have a direct effect on White Island, he said.
It would have to be a large quake, within kilometres or tens of kilometres away, to affect the island.
There have been a series of moderate-sized quakes this week along the New Zealand plate boundary, which scientists were monitoring.
White Island remains at alert level 1, or minor volcanic unrest.
Two other earthquakes shook people at the top and the bottom of New Zealand's South Island overnight.
The first and strongest of the quakes struck in Fiordland, 75km west of Te Anau, about 1.30am on Thursday (2330 Wednesday AEDT). It was a magnitude 4.8 earthquake and was at a depth of 14km.
GeoNet described it as being of strong intensity, but it wasn't widely felt given the remote area.
Ten minutes later, another quake struck in southern Marlborough, about 45km east of St Arnaud in the Nelson Lakes area.
The magnitude 4.6 earthquake was at a depth of 24km and was felt in Wellington and Christchurch.
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