WELLINGTON (Reuters) - Three people were killed and several injured after an unusual storm, described by witnesses as a "mini tornado", hit New Zealand's largest city of Auckland on Thursday, toppling trees and ripping debris from a construction site.
The tornado, driven by a powerful storm cell, tore concrete slabs from a building site and dropped them onto a truck, killing two people inside, a fire services spokesman said.
Rescue teams were searching a school site for workers thought to be trapped beneath fallen concrete blocks in the west Auckland suburb of Hobsonville, The New Zealand Herald newspaper reported.
Details on the third death were not immediately available. At least seven people injured in the storm were sent to hospital.
"I saw it coming across the river, the air went very electric and the sky went black. And then the wind started to whistle. This was like a juggernaut roaring through here," witness Suzanne McFadden told New Zealand's Newstalk ZB radio.
Hobsonville is the site of a new town centre near Auckland, which is home to 1.3 million people, roughly a third of the New Zealand population.
Military personnel were going from door to door in the area to check if more people were trapped and authorities warned of more severe weather to come later on Thursday.
New Zealand has been hit by several natural disasters in recent years, including a magnitude 6.3 earthquake that struck the southern city of Christchurch in 2011, killing 185 people. Another tornado in Auckland last May killed one person.
The Christchurch quake caused damage worth NZ$15 billion to insurers, making it the country's costliest natural disaster.
(Reporting by Rob Taylor; Editing by Paul Tait)