Three people are dead, seven in hospital and hundreds left homeless after a tornado ripped through parts of Auckland.
The tornado, which hit the suburb of Hobsonville about 12.15pm (10.15am AEDT), ripped roofs from houses, toppled trees and sent debris flying onto cars.
Up to 150 homes were badly damaged, leading to 250 residents being given shelter at the Whenuapai Air Force base.
Two construction workers were killed when a concrete slab landed on a truck at the building site of a secondary school.
A third death was later confirmed, believed to be caused by a fallen tree.
Authorities ordered Hobsonville residents to take shelter in their homes throughout the afternoon with the MetService, New Zealand's weather bureau, warning of the potential for further tornadoes.
The residential centre of the tornado's destruction was Wallingford Way, in Hobsonville; a street lined with Defence Force state housing.
Every house in Wallingford Way was damaged in some form with broken windows, damaged roofs and trees uprooted.
Most residents were evacuated from the street but army and emergency services continued to work to clear the debris.
A resident said they saw wheelie bins and pot plants flying past their windows and were forced to duck for shelter as windows were smashed in.
The highest windspeed recorded at Whenuapai airbase, close to the time of the tornado, was 110km/h. That constituted a severe gale but would not have been the speed in the tornado itself, which was not measured.
The tornado was accompanied by heavy rain, with hundreds of homes losing power, several major roads closed and delays caused at Auckland International Airport.
Prime Minister John Key, whose electorate covers the damaged area, extended his sympathy to friends and family of the victims.
Toni Hayward, administrator at the Open Wananga Office in Hobsonville, saw the tornado rip through the area.
"It came right through here and picked stuff up an threw it on the road."
"The sky went all dark and there was a big clap of thunder, all the trees were flattened."
Hobsonville RSA cook Deborah Carlson said she was trapped in her car during the storm, too terrified to go outside.
"I was just sitting there because it was pouring with rain and I thought I'd wait it out. But then my car started shaking and there were things flying everywhere. I thought it was going to flip, I was terrified."
Casey Davenport, who lives in Hobsonville, was at work when the weather started to turn.
Fallen or uprooted trees and pieces of debris were blocking the road to her house, which she said was leaking like a sieve".
"We're missing tiles, broken windows ... it's full of water now because it's leaking. But we're one of the better ones I think."
Brendan Muir, who was working at Hobsonville Point, said he was sitting in a ute when the tornado hit.
"It was just mayhem. I had to put my seat belt on, I thought it was going to flip."
Muir said that, around him, he could see trees "that looked like a plane had crashed into them", walls and fences knocked down and Portaloos scattered about.
He said for about 10 minutes there were so many sirens sounding it "seemed like 9/11".
Frances Schuster said the tornado only lasted 12 seconds but was terrifying.
"It went blurry for a while, it just happened so fast. It was really loud and the windows were shaking."
Part of a roof fell onto her car.
In May, last year, a tornado in Albany, on Auckland's North Shore resulted in the death of construction worker Benedict Dacayan.
The 37-year-old North Shore resident worked for Fletcher Building and was part of a team of 15 helping to demolish the old Placemakers building in Albany when the tornado lifted him into the air and threw him into a concrete wall.
The tornado caused extensive damage to sectors of Westfield, Pak 'n' Save and other commercial locations and tossed cars in the air.
In September, last year, more than a dozen houses were damaged by a tornado that ripped through several streets in the West Auckland suburbs of Avondale and Te Atatu South.
In September 2009, another tornado tore the roof off a house in Ramarama, South Auckland and in July 2008, four homes were damaged by a twister in Glendowie. A person was injured in July 2007 when a tornado tore roof tiles in Botany.