It touched down at about 1500 (0300 GMT) in the city's Albany area and then moved south, felling trees and tearing roofs off houses.

Cars were overturned by the tornado, which left a 5 km-long (three mile-long) trail of damage.

A roof was also ripped off a shopping centre in Albany, local media said.

Earlier reports had put the death toll at two.

"Initial reports that there were two or three dead are incorrect and we can only confirm one death at the moment. We believe that to be accurate," said local police commander Gary Davey.

Auckland Mayor Len Brown said he was surprised more people had not been killed.

New Zealand's stuff.co.nz news website said that at least 18 people had been taken to hospital.

Police warned local residents to stay inside until the weather settled.