The effects of the 7.8 earthquake and aftershocks that struck Fiordland on Wednesday 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, there was 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.
About 50 people were also evacuated from homes and resorts on Lord Howe Island.
Tourists and residents were relocated from low lying areas to the old Met site on higher ground for about three hours on Wednesday night, a representative from the Arajilla Retreat resort said.
"We were in our cars for two or three hours," the representative, who did not wish to be named, told AAP.
"There were 40 or 50 of us maybe, but a lot of people live up the top of the island anyway."
Most of the island's residential and tourist accommodation was on high ground, she said.
Tsunami threats from NZ
An expert from the University of New South Wales says Australia will face further threats from tsunamis because of an earthquake-prone area off the New Zealand coast.
Dr Dale Dominey-Howes says there has been about 40 earthquakes of various magnitudes in recent history in the area where a major undersea quake off New Zealand's South Island coast sparked tsunami alerts on Wednesday night.
"There's no evidence at the moment to say they are becoming more common, but certainly they are being recorded regularly now because of the amount of high-tech equipment we have in use," Dr Dominey-Howes said.
NSW State Emergency Service were on high alert after Wednesday night's earthquake.
The initial threat of a large wave hitting the Australian east coast appeared to have passed by 1am.
But the Pacific Tsunami Warning Centre said strong currents could still affect parts of Tasmania, Victoria and NSW.
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