Clean-up is underway after a tornado hit the Kāpiti Coast, leaving about 20 properties in Paraparaumu damaged, with a roof ripped off one and another lifted from its piles.
Earlier, a small tornado swept through Waitara, in Taranaki, damaging a house, while MetService is warning more thunderstorms could be in store across the country.
Kāpiti Coast District Mayor Janet Holborrow said around 20 properties had been damaged following a tornado in Paraparaumu on Tuesday morning.
There was damage to roofs, trees, fences and glass, but only two houses were significantly affected.
Holborrow said building assessments would be under way in the next few days.
But in the meantime, more extreme weather was on the way, she said.
"We're really encouraging people to tie down trampolines, tie down outdoor furniture, make sure there's nothing around the property that could blow away because we have seen damage to properties with items coming from other properties."
Council teams had been working on Tuesday to secure the damaged homes from further destruction, Holborrow said.
A teenager is in hospital, after suffering severe cuts and a collapsed lung when his sleepout was destroyed.
Fire and Emergency assistant commander Stephen Hudson told Morning Report the 16-year-old was asleep in a structure that was completely destroyed.
Two houses on Aorangi Road had been especially hard hit, Hudson said.
"One has had its roof completely removed, the one next door has been badly damage and it's been lifted off its piles and put back down again, so there's structural damage with that."
Hudson said FENZ was working with the Kāpiti Coast District Council to do a rapid assessment of the damaged properties.
He spoke to RNZ from Aorangi Road, and said the occupants of the two homes badly damaged would not be going back in them tonight.
Hudson said USAR was also doing a damage assessment by drone.
Some roads are down to one lane because of downed trees and powerlines.
The Kāpiti Coast District Council said ensuring roads are open and safe to use, is a priority, but the trees cannot be cleared until the areas are made safe from fallen power lines.
The council said it has contacted affected residents and will organise temporary accommodation or other welfare assistance if needed.
Tristan Deihl said he woke up to his daughter screaming as the tornado ripped through Aorangi Road, Paraparaumu, just after 5am.
He said it lasted about a minute and was a scary ordeal.
Paraparaumu resident Sam said it was "chaos" and "happened so quick".
"It was some loud crashing and banging and shaking and then it was all over - damage done.
"One of our big trees down the front fell down onto the road ... sheets of iron in our back yard, Pink Batts everywhere, so someone's doing it a lot worse than I am."
Power lines were also down, several trees were been blown over and fences destroyed. More than 2000 properties were without power after the tornado first hit.
Lines company Electra said 144 were still without power earlier on Tuesday, but by mid-afternoon all houses had had their power restored.
Fire crews attended the Metlifecare facility where there was suspected roof damage.
The tornado was reported to have swept through Nikau Valley before making its way out to sea.
Fire and Emergency said there was an earlier tornado in Taranaki.
The small tornado lifted the roof off a house in Waitara about 1.15am.
It follows an Easter weekend of extreme weather, when about 50 properties were damaged after a tornado tore through the Tasman district near Nelson on Monday, a day after another tornado caused hit East Auckland, toppling trees and damaging at least 51 homes.
MetService is warning that much of New Zealand still needs to be on alert for potential tornadoes and severe thunderstorms today.
Severe thunderstorm watches are in place for Buller and Westland to 6pm, and Auckland, Great Barrier Island, Coromandel Peninsula, Waikato, Waitomo, Taumarunui, Bay of Plenty, Rotorua, Taupō and Taranaki to 8pm.
MetService meteorologist Andrew James said there is still an unstable air mass affecting the North Island from Taranaki north, and the northern parts of Westland and Buller on the South Island's West Coast.
"What we are seeing is quite a lot of thunder and lightning activity as well with this system and as that system moves down over Aotearoa, we're going to see those thunderstorms do pick up and tornadoes are always associated with a thunderstorm so we are still forecasting the possibility of a few some small tornadoes throughout the course of today."
James said the area for possible localised tornadoes and damaging winds is widespread, so the best advice is to stay up-to-date with MetService and be prepared for bad weather.
NIWA scientist Chris Brandolino told Morning Report low pressure over the Tasman was creating the ideal conditions for thunderstorms and heavy showers.
"Air flow spins clockwise around low pressure so that means we're getting a lot of warm humid air.
"So the atmosphere is primed for what we all convection, and that's basically heat-driven thunderstorms, heavy showers."
There could be more showers and thunderstorms over Northland and Auckland, Coromandel, and perhaps Bay of Plenty, Gisborne, Taranaki, Manawatū, and towards Wellington.
"There's so much wind energy in the atmosphere, thunderstorms can tend to focus that wind in a small area and create damage, heavy rain and hail."
On average New Zealand had seven to 10 moderate tornadoes a year, he said.
⚡ This is what 24 hours of lightning looks like. 10 April has been a very active day for lightning with 33960 strikes recorded on our network. Of these, 8827 were over land.— MetService (@MetService) April 10, 2023
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Buller 483 pic.twitter.com/3GKr16xo36