A tornado has ripped through Hobsonville in Auckland and three people are confirmed dead.

Stuff.co.nz is reporting St John Ambulance confirmed two people died at a construction site in Hobsonville earlier today and one person was later confirmed dead.

Power lines and trees are down in the Hobsonville area after a tornado hit the region this afternoon. Photo: Facebook.

The tornado hit Auckland about 12.15pm ripping roofs off houses and bringing down trees and powerlines.

Numerous flights out of Auckland International Airport have been cancelled.

Prime Minister John Key has released a statement expressing his condolences to the friends and families of those who died.

'A thunderstorm and tornado struck West Auckland around 1pm today, tearing down trees, and ripping roofs from houses,” Mr Key says.

'This must have been an extremely frightening situation for many people in the local community.

'I'd like to thank the emergency services staff, who are responding to the situation. It's critical they are able to focus on the response."

WeatherWatch.co.nz forecasters say another band of thunderstorms and torrential downpours are moving back in to West Auckland - just 90 minutes after the first set.

'We are advising people to remain indoors until the torrential rain and possible thunder has passed, most likely over the next hour or two,” says head weather analyst Philip Duncan.

Weatherwatch.co.nz says people should keep up to date with the latest forecasts in case any of the watches around the country are upgraded to warnings.

A heavy rain warning remains in place for the Bay of Plenty with heavy rain expected to about the eastern ranges.

The MetService is predicts around 60 to 80mm of rain in addition to what has already fallen in the next few hours until 9pm.