Sharp quake wakes South Islanders

An earthquake this morning under the south Tasman Sea was the largest in the world since 2001 but it did little more than wake people up in the south of the South Island.

Latest estimates from Geological and Nuclear Sciences (GNS) suggested the 3.58am earthquake was centred 430km west of the Auckland Islands, southwest of New Zealand, at a depth of 10km, and may have been as much as 8.1 on the Richter scale.

"It was enough to wake me up," Senior Sergeant Neil Cruickshank of Invercargill Police told NZPA. "It was reasonably prolonged but it felt about half the strength of the one we had a few weeks ago."

That earthquake, on November 23, was of a smaller magnitude -- 7.2 on the Richter scale -- but was only about 70km off the Fiordland coast.

Mr Cruickshank was not aware of any earthquake damage caused in the area today.

Earlier estimates suggested today's earthquake was also 7.2 on the Richter scale, located 380km north of Macquarie Island at a 33km depth.

"We now have it recorded at 7.3 but it's difficult for us to measure because it was so far away from us," GNS duty seismologist Ken Gledhill said.

"But international data from institutions like the US Geological Survey suggests it was 8.1, which in our measurements is a great earthquake."

More than 80 people logged on to the GNS website to say they felt the earthquake, though after the November 23 earthquake there had been more than 800 reports, Mr Gledhill said.

Today's quake was felt in Tasmania, causing buildings in parts of the state to shake for up to 15 seconds. No one was injured.

- NZPA