There are no reports of any serious injuries from the earthquake, which had a magnitude of 7.1.

But 60 primary school children staying at a remote hostel at Deep Cove were stranded by a landslide which blocked a road, Reuters news agency reports.

The quake's epicentre was off the coast, 70 kilometres (43 miles) west of the tourist resort of Te Anau, according to New Zealand's Institute of Geological and Nuclear Sciences.

The tremor was felt across a large part of the South Island and state-owned National Radio reports that power was briefly cut to two small towns.

But all of the region's hydro-electric power stations are still generating, Reuters reports.

The shocks also reached the Australian city of Sydney, 2,140km (1,330 miles) away, the Associated Press reported.

'Lucky'

Senior Sergeant Ian Freeman of the Southern Communications Centre said police were inundated with calls, with 115 emergency calls in half an hour.

"We've had stuff falling off walls and that kind of thing but no serious damage nor injuries reported," he told the New Zealand Press Association.

Correspondents say New Zealand records thousands of earthquakes a year, as it lies on a junction between two tectonic plates.

A tremor with a magnitude of 4.7 struck 40km (25 miles) north-west of Te Anau on 20 August, Reuters news agency reported.

Seismologist Dr Ken Gledhill said it was lucky the tremor had been centred on such a remote area as "an earthquake of this size near a population centre could cause a lot of damage".