WELLINGTON: An unusually destructive tornado swept through neighborhoods around New Zealand's largest city Thursday, killing three people and forcing 250 more to evacuate damaged and powerless homes.    

The small tornado hit Hobsonville and Whenuapai, western suburbs of Auckland, during a midday storm that also uprooted trees, damaged buildings and caused flooding that closed roads.

Authorities said that as well as those who died, seven people suffering a range of injuries were admitted to hospitals.

Thursday's tornado was the deadliest in New Zealand in more than 60 years. Although the country reports about seven tornados on average each year, most are small, mild and do little damage. New Zealand's temperate maritime climate means it isn't prone to the large, destructive tornados that plague places like the American Midwest.

Auckland Council spokesman Glyn Walters said the storm made about 150 homes uninhabitable. He said some of those homes had roofs torn off or were severely damaged while others had more minor damage or had lost power. He said 250 residents were taken to an air force base at Whenuapai, where council staff and welfare workers were assisting them.

The worst weather appeared to have passed by midafternoon, Walters said. ''It's clearing up slightly but people need to be careful out there,'' he said.

Auckland Fire Service Area Commander Larry Cocker told The Associated Press that three people had died in the storm.

Walters said one person was killed when hit by a tree and that some others who were killed or injured were workers who were building a school.    Several New Zealand media outlets reported that two of those who died were in an accident involving a slab of concrete.

Richard Turner, a meteorologist with New Zealand's National Institute of Water and Atmospheric Research (Niwa), said New Zealand isn't prone to the intense surface heating that helps create the huge and violent tornados seen in the central United States. But he said even relatively small tornados like the one on Thursday can cause damage and death.

Tornados in New Zealand are typically about 30 meters wide and last for only a few minutes.

Daniel Corbett, a meteorologist with government forecaster MetService, said there had been some very warm, humid air ''like soup'' sitting over Auckland for several days before thunderstorms hit, creating the conditions for Thursday's tornado. He said he expected the weather system would move away from the country Thursday night.

The tornado equaled the deadliest recorded in New Zealand's history. In 1948, three people were killed when a tornado hit a suburb in the city of Hamilton.