New Zealand downgrades tsunami alert after quake

New Zealand authorities withdrew a tsunami warning Thursday following a 5.9-magnitude quake on the western coast of the South Island.

"This advisory represents a downgrade from warning," the National Emergency Management Agency said, explaining that the quake was smaller than its initial estimate.

After first warning people in affected areas to "move immediately" to high ground, it now advised them to be careful of "strong and unusual currents" at the shore.

The earthquake was 76 kilometres deep and struck 83km west of popular South Island tourist centre Queenstown, the USGS said.

Authorities initially warned of possible land inundation and ordered people in the tourist hotspot Milford Sound to evacuate to high ground.

The manager of a hotel in nearby Te Anau told AFP she "could hear it coming first".

"The shaking was very severe. I thought it was the big one we've been told is coming."

No damage had been reported on Thursday night.

New Zealand is formed where the Australian and Pacific plates meet, and is frequently rocked by large earthquakes and volcanic activity.

A 5.0-magnitude quake was also felt off North Island earlier on Thursday.

Meanwhile, a 6.3-magnitude earthquake in South Island city Christchurch in 2011 killed 185 people.