More than 200 people have been torn from their homes in the wake of a tornado that killed three people and injured seven north-west of Auckland Thursday.
Civil Defence said the casualties occurred at the construction site for a new school at Hobsonville Point.
The twister hit a one-kilometre zone in Hobsonville at 12:30 pm, hitting the school construction site with deadly force.
It appears giant concrete slabs toppled onto a work truck, crushing those inside.
Hawkins Construction says there were "fatalities and injuries suffered by a number of subcontractors" at its Hobsonville School building site.
Police will be releasing further information about the fatalities and injured once their investigations are complete, the company said in a statement.
Civil Defence said about 150 homes are uninhabitable or without power at the Whenuapai Air Force base, and a further 70 homes in the wider area have been evacuated.
Houses deemed uninhabitable have been marked with a red cross.
Electricity has also been off in other parts of Auckland including Meadowbank and St Johns. Power was cut from shops at the Westfield West City mall and the carpark was closed due to flooding. Auckland Council building inspectors attended the worst affected areas.
The NZ Transport Agency re-opened State Highway 18, the Hobsonville Motorway, after it was closed for about two and a half hours. Storms brought down light poles, disabled motorway cameras, left sections of the motorway littered with debris and caused flash flooding on roads across greater Auckland.
Police called on motorists not to venture out unless necessary.
Flights in and out of Auckland airport were cancelled or delayed due to "severe storm safety protocols" being implemented. A number of arriving flights were diverted to other airports and agencies were "working to establish a priority order" for when flights resume, an airport spokesman said.
The Fire Service was inundated with calls and said there appears to be "significant building damage" sustained from the storm.
In a matter of moments roofs were lifted and trees came down. One man said: "I lost my garage and trampoline and a few other bits and pieces. And just checking out the neighbourhood now."
Residents said people were screaming and in tears when the tornado struck.
With files from CNN