A tornado tore through west Auckland on Thursday, killing three people, injuring several others and destroying homes in its wake.
The severe weather event happened about 1pm on Thursday, with the tornado hitting a subdivision of Hobsonville, leaving a trail of damage and debris.
Three people working at a construction site were killed, while seven others have been injured. Three people remain in Auckland Hospital in a stable condition, while four were taken to North Shore Hospital with minor injuries.
Plumber Sam Nuttall was working at the site with 50 others where a high school is being built and said he saw two workers hit by large concrete panels.
Mr Nuttall told Radio New Zealand's Checkpoint programme that one person was stuck between a truck and a panel, while the other was underneath the panel. Debris flew everywhere and steel was thrown around. He said he had never seen weather like that before.
In a statement on Thursday, Hawkins Construction executive general manager Dan Ashby said the company's immediate focus was on supporting the affected workers' families and its staff and sub-contractors on site. Mr Ashby said the company is assisting police and other services.
Emergency services said there is extensive damage to an area of about one square kilometre in Hobsonville, with less serious damage to properties and debris scattering the roads in the wider western suburbs.
Some 120 homes have been severely damaged and another 60 homes need to be assessed, including some near the Whenuapai Air Force base. About 230 people have visited the base to register their details. Group Captain Kevin McEvoy says those evacuated so far have found alternative accommodation.
Deborah Booty, whose Defence Force house in Wallingford Way was badly damaged, told Checkpoint the tornado sounded like a freight train coming through.
"It was pretty noisy. I rang my husband while I was in the wardrobe and he was telling me to calm down and to breathe. When I thought it was over I came out, because I could hear water dripping in the ceiling and I didn't want to get caught in a ceiling collapse."
Auckland Mayor Len Brown said the winds cut through the area "like a knife through butter" and Civil Defence staff would work around the clock in the clean-up effort.
Civil Defence, along with other emergency services, would assess homes over the next few days to understand the extent of the damage and whether or not people could return to them.
The Fire Service said it received up to 100 calls from distressed residents throughout wider west Auckland. Police are confident they have found everyone who needed assistance.
In May last year, a tornado struck the Auckland suburb of Albany, killing one man.
Power out in some suburbs
Lines company Vector said about 1300 customers are without power on Thursday. Suburbs affected included Hobsonville, Whenuapai, Greenhithe and Riverhead.
The company said power is unlikely to be restored before Friday morning.
Road and transport
There were big delays at Auckland Airport, with some cancellations. Flights began to take off again on Thursday night, but there was a large backlog of travellers to clear.
Roads in the region have reopened, including State Highway 18, also known as the Upper Harbour Motorway. Police warned people to drive safely and be aware of flooding.
Bus services in west Auckland are operating, but faced major delays. The West Harbour Ferry Service was being replaced with a bus at 5.30pm, but other ferries were operating to schedule. Train services were also running to schedule.
Prime Minister John Key expressed his support for those affected on Thursday, describing the situation as a result of a freak and cruel act of nature. He offered his condolences to the families of those killed.
Labour leader David Shearer also expressed his sympathy to the families, saying it was deeply shocking to lose loved-ones in such a sudden and tragic way.
He said Labour would do everything it could to support the many families who find themselves homeless and in the weeks ahead as they rebuild their properties and lives.
Auckland Mayor Len Brown spent Thursday afternoon in the area with emergency services, inspecting the damage and meeting some of those affected. He said it is a real tragedy and his heart goes out to the community and the company concerned.
The Ministry of Education also expressed condolences for the deaths and injuries of the workers and said it would co-operate with any health and safety investigation.