The effects of the 7.8 earthquake and aftershocks that struck Fiordland last night were felt as far away as Australia.
The quake, which was centred 100km northwest of Tuatapere and 12km deep, struck at 9.22pm and triggered an alert from the Pacific tsunami warning centre in Hawaii.
In Sydney, a performance at Bondi Pavilion was cancelled and the theatregoers were evacuated, while other Sydney residents were warned to keep away from the water's edge.
However, the prediction was for only a small surge of water, about 17cm high, and the tsunami warning was cancelled after its size was confirmed on arrival at Bluff at about 10.30pm.
There were surprisingly no reports of major damage from the quake, which was felt widely throughout the South Island and as far north as Taranaki.
It was followed by two sizeable aftershocks, one 19 minutes after the initial quake measuring 6.1, and another at 1.50am measuring 5.9.
A Southland police spokesman reported a fallen power pole in Otatara and a burst water main on Lincoln's main street, but said he expected more reports of damage would come in as people opened up their businesses today.
GNS Science geologist Bill Fry said scientists worked into the night to gather enough details on the site of the quakes to be able to assess any continuing risks to people or property.
"The shallower an earthquake is, the more shaking there's going to be -- and this was quite shallow," he told NZPA.
An Invercargill man told NZPA the initial quake lasted at least a minute.
"Things just started to rattle a bit, then the house started to sway."
He and his wife got their three young children out of bed and huddled under the dining table to wait it out.
Cracks had appeared around several door frames, he said.
Central Southland man Warren MacPherson said a hanging light in his house would have been swaying "a good six inches each way".
He was on the phone when the quake struck and rushed outside.
"By geez, there was a fair bit of movement," he said.
Invercargill police Inspector Olaf Jensen said the quake was significant enough to send staff into doorways.
He described it was a strong, rolling quake rather than a sharp jolt.
The controller of Southland's civil defence emergency management group, Neil Cruickshank activated the region's emergency operations centre to assess damage reports and said the region had been given "a good shake" .
"Phone services were down in east Invercargill and power was out for some time in the suburb of Otatara because of the earthquake," he said.
Southland District Council said there were no reports of substantial damage in the Milford and Te Anau areas.
More than 14,000 earthquakes are recorded in New Zealand annually, but only about 20 are stronger than 5 on the Richter scale.
