At least two people have been killed and many others injured when a tornado ripped through Auckland, New Zealand's largest city.

Many of the injuries occurred when the roof of a large shopping mall collapsed in the suburb of Albany.

Witnesses told of seeing victims stunned and bleeding as buildings were destroyed, cars thrown up into the air, and trees uprooted.

The tornado, packing winds of 125 miles per hour, wreaked a trail of destruction across the North Shore, a few miles from the centre of the city of more than a million people.

It struck about 3pm local time, when shops and offices were at their busiest.

Emergency services say at least 20 people were taken to the local North Shore Hospital, with others going to the main Auckland Hospital.

Some of the injuries, which included lacerations and fractures, were known to be serious.

Many buildings were badly damaged with roofs being torn off, including the Albany Mega Centre shopping mall and a hardware store.

Martin Sibrits, of Rebel Sports shop, said the tornado was huge.

"It was simply unbelievable."

He saw pieces of iron roofing flying through the air, up to 300ft high.

Mr Sibrits said the Placemakers hardware store "is looking like a bomb site".

Witness Kate England said she watched a grey car being lifted 20ft up into the air near a roundabout.

"It was the most surreal experience."

Reuben Moore, another witness, said: "I suddenly heard what sounded like a jet engine, so I ran out to the front of the store to see a tornado at the end of the car park.

"There were cars tossed around like matchsticks.

"Stuff from roofs was all over the place, air conditioners from buildings were landing on cars in the car park."

The tornado disappeared as quickly as it came, lasting about 15-20 seconds, Mr Moore said.

"There is sheer panic everywhere, it's just so shocking because it happened during a pretty busy time of day."

The Auckland Civil Defence Emergency Co-ordination Centre was activated to support emergency service operations.

Officials were arranging emergency accommodation for anyone needing it and the death toll was expected to rise.

Tornados are not uncommon in Auckland but they are usually so small as to cause little or no damage.

In May 1991, one man died when debris spread by a tornado hit him while he was driving a bulldozer in Albany.