'Felt like a truck': Locals describe 5.9 magnitude Southland earthquake

A strong earthquake in the South Island that sparked a tsunami warning felt like a truck driving past, a Wānaka couple say.

The quake hit 40 kilometres north of Te Anau at 9.14 pm on Thursday evening.

It was originally said to be magnitude 6.3 but has since been downgraded to 5.9.

Evacuations were called for and a tsunami warning was issued, although the evacuations have been cancelled and the warning downgraded to an advisory and then cancelled altogether.

"The advisory has been cancelled because no tsunami signals have been detected by Earth Sciences NZ for approximately the past two hours following the event," the National Emergency Management Agency said at 11.26 pm.

"This indicates that there is no ongoing tsunami activity affecting the area, and the threat has now passed."

Wānaka couple Mullion and Ken said they had "had just gone to bed" when they were both woken by the shake.

"Both of us were woken by the bed moving, and it did feel like a truck was driving close past the bedroom."

One resident of Bannockburn in Christchurch described feeling "long, shallow waves".

Christchurch resident Vicki Newbegin said she felt the quake from her 10th-storey apartment.

"To me it felt more like a rolling motion... probably because Christchurch is a reasonable distance and I think it would have been a wave of the earth's movement rather than a sudden shock."

She said she had felt some aftershocks since.

GeoNet has reported several smaller quakes since the initial shake, though all are of 'light' or 'weak' intensity.

Southland mayor Rob Scott said he had heard of possible damage to houses "in terms of cracking and the like".

He is currently in Auckland but says he has heard from people in Milford Sound who "did do the right thing" and got to higher ground at the time.

"It's been quite a shake down there... but it's quite pleasing to hear … there's no need for an evacuation," Scott told Nights.

Earth Sciences New Zealand scientist Bill Fry said the quake would have generated strong shaking near the epicentre.

He said he is hoping the aftershocks reduce in frequency, and don't cause damage.

"We're still looking at the evolving aftershock situation, vigilant and with heightened monitoring to see if there are any larger after-shocks maybe that might have the potential to cause damage, or cause landsliding."

Fry said there's been quite a few big earthquakes in the region in the past two decades, including the 7.8 2009 Dusky Sounds Earthquake.

-RNZ