A violent storm is battering the Wellington region late on Thursday, leaving tens of thousands of households without power. The council is warning people to stay inside to avoid flying debris as winds exceeding 140km/h lash the capital.
The MetService said the wind reached 200km/h at Mount Kaukau in the suburb of Khandallah late on Thursday and 142km/h at Wellington Airport.
Lines company Wellington Electricity said 25,000 customers were without power because of damage caused by high winds and torrential rain. It said trees and debris are being blown into lines, and staff are trying to repair the damage across Wellington City, Porirua and the Hutt Valley.
Transpower said people who still have electricity would find their lights are flickering because the winds are clashing transmission lines together.
Wellington City Council spokesperson Richard MacLean said he had received many reports of flying debris.
"We've got multiple reports of trees down, powerlines down, broken windows, structural damage and all sorts of problems. So in other words, don't go outside - stay indoors."
Mr MacLean said a house has lost its roof in the suburb of Kingston and listeners have told Radio New Zealand that roofing iron was blowing about on roads in Newtown.
Emergency services said they are very busy. The Northern Police Communications Centre said 90% of the calls it is getting are ones that can't be answered by its overloaded Central branch based in Wellington.
The New Zealand Transport Agency is advising people to be extremely careful when driving on motorways in Wellington.
Spokesperson Anthony Frith said large waves from Wellington Harbour are hitting the Hutt motorway and a slip is blocking one of the south-bound lanes on State Highway 1 through the Ngauranga Gorge at the north of the city.
Conditions are expected to ease in Wellington on Friday afternoon.
Storm moving north
High winds and thunderstorms were also hitting the northern-most parts of New Zealand late on Thursday. MetService said it had recorded wind gusts of 110km/h in western parts of Northland and at Manukau heads near Auckland.
Forecaster Heath Gullery said unstable, squally showers would bring thunder, lightening and hail. Severe gales were forecast for Taranaki and Whanganui overnight.
Flights and ferries cancelled
The southerly gales forced Air New Zealand to cancel all flights in and out of Wellington. They had been suspended at 5.30pm and the decision to cancel was made at 6.15pm.
Air New Zealand said the bad weather had already disrupted many other flights during the day, especially in Queenstown.
Jetstar said it had also cancelled its four flights in and out of Wellington.
All Interislander ferry services have been suspended ahead of predicted waves of up to eight metres high on Friday. The last sailing was a cargo service at 6.30pm on Thursday.
All train services in Wellington have been cancelled.