Tsunami threat passes after powerful New Zealand earthquakes

Three tremors ranging from 7.2 to 8.1 magnitude struck off the coast of North Island

A man scans the horizon from high ground for any sign of a tsunami near Waitangi, New Zealand, on March 5, 2021 after a powerful 8.1-magnitude earthquake struck the ocean off the coast. AP

A series of powerful undersea earthquakes struck north-east of New Zealand on Friday, but tsunami waves that forced many people on the country's North Island to flee to high ground passed without causing substantial damage.

Officials predicted that waves could reach three metres above high-tide levels after the quakes – the strongest a magnitude 8.1 – but the threat had passed by the afternoon, the National Emergency Management Agency said.

"It's hard not to feel like our country is having a run of bad luck, when you have an earthquake, tsunami and pandemic to contend with all in one day," New Zealand Prime Minister Jacinda Ardern said.

Video footage on social media showed surges of water entering a marina in Northland and on the North Island's East Cape region.

Earlier on Friday, workers, students and residents in areas such as Northland and Bay of Plenty, on the north coast near Auckland, fled beachside towns for higher ground after the three quakes, striking in an eight-hour period, triggered blaring tsunami sirens and warnings to evacuate via text messages.

An emergency alert was issued for coastal areas around the South Pacific country of five million, with people told to stay away from the shoreline. There were no reports of damage or casualties from the quakes.

The third and strongest quake struck the Kermadec Islands, a mostly uninhabited group of islands about 800 kilometres north-east of North Island, on Friday morning, shortly after a 7.4-magnitude earthquake in the same region. Earlier, a 7.2-magnitude earthquake struck just east of North Island.

Linda Tatare, a resident of Anaura Bay, on North Island's east coast, said the small community of about 50 left for higher ground in the morning.

"Everyone, and their dogs, are up in the hills," Ms Tatare said.

"We are safe. We can all see our properties from here."

Tsunami warnings were also put out for Pacific islands including New Caledonia and Vanuatu, while smaller tsunami waves may be recorded as far away as Antarctica and parts of South America, the US Pacific Tsunami Warning Centre said.

Friday's series of quakes was caused by tectonic movement on the boundary of the Australian and Pacific plates, part of the so-called Pacific Ring of Fire on which New Zealand sits.

A decade ago, a 6.3-magnitude quake killed 185 people in the South Island city of Christchurch.

Australia issued a tsunami threat for Norfolk Island, a tiny Australian territory with about 1,750 residents, but said there was no threat to the mainland.

Norfolk Island residents in areas threatened by land inundation or flooding were advised to go to higher ground or inland, the Bureau of Meteorology said, as small tsunami waves hit the coastline.