Key Points:

Around 200 Auckland households are still without power this morning after a violent storm that had electricity workers out all night.

Some others, mostly on the North Shore, have no hot water - and they may be without it until tomorrow lunchtime.

Vector's network operations manager Graham Petrie said there was an average of around 25,000 homes without power at the height of the storm.

Mr Petrie said the outages are in pockets all over the region, and he is asking customers to call Vector or their power retailer if they are affected.

Winds of up to 150km/h lashed Auckland yesterday, causing chaos that led to hundreds of emergency calls to police and the Fire Service, disrupted travel and closed the Sky Tower.

The rain and winds were caused by an intense low which swept over Waikato and past the Coromandel Peninsula.

The Fire Service communications centre said up to 40 crews worked on 500 weather-related emergency calls received between midday and 8.30pm.

Shift manager Jaron Phillips said most calls were from Aucklanders, particularly in the western and central suburbs.

Incidents reported included fallen and arcing powerlines, trees falling on to powerlines, roofs lifting and broken windows in homes.

Inspector Gavin Macdonald from the police northern communications centre said staff received more than 500 calls, most of them weather-related, between 5pm and 6pm.

MetService forecaster Oliver Druce said the Sky Tower and Manukau Heads were hit by gusts of about 150km/h during the afternoon.

The central city and parts of the Hauraki Gulf had winds of up to 130km/h, which disrupted ferry and air services.

The Birkenhead ferries were replaced by shuttle services in the afternoon and Waiheke Island passengers were delayed because of the wind and large swells.

Fullers Group chief executive Douglas Hudson said the weather also caused damage to two pontoons on the Waiheke wharf, raising safety concerns.

Flights from Auckland Airport were grounded because of concerns for the safety of baggage handlers exposed to the extreme winds.

An Air New Zealand spokeswoman said it was unsafe for staff to work in the conditions and flights were delayed for up to an hour until the winds fell.

The Sky Tower was closed during the afternoon after it started to sway in the high winds.

SkyCity spokeswoman Rosalie Nelson said the closure was more for comfort reasons than safety. The tower was designed to sway up to a metre in extreme winds.

"But having cutlery and glasses shaking while you're dining would probably not be that comfortable."

Reports of city roads being temporarily blocked were common, motorists had to dodge rubbish bins, branches and other debris, and part of Whitford Rd was closed after powerlines fell and blocked it.

Vector said power was cut to 22,000 Auckland homes - 15,000 in Auckland City and 7000 on the North Shore.

Motorists travelling over the Harbour Bridge were warned to take care because of the gusts, and the police said several crashes appeared to be weather-related.

The Coastguard was kept busy, dealing with reports of 10 yachts seen aground or drifting.

Duty officer Katherine Andrews said conditions were so bad that little could be done in most cases as it was not worth risking lives to save boats.

A Coastguard crew was sent to help two people who got into difficulty trying to save a yacht that went adrift near Waiheke.

Coastguard staff said they saw waterspouts forming over the Waitemata Harbour.

"We have had three or four of them and watched them form and just disappear into the sky," said Ms Andrews.

In Tauranga, a mini-tornado pushed a 40-year-old 18m eucalyptus tree off its roots and then swept 50m down a driveway where it knocked large branches off a pohutukawa tree across the street.

The tree crashed into the home and car of ecologist Kate McGrath.

"From an ecologist's point of view, it was definitely an extreme weather event," Ms McGrath said. "There was a huge lot of rain and then wind, and the next minute it was 'crash, bang'."

A large section of the tree fell on to the roof of Ms McGrath's rented harbourside unit, smashing windows and putting a hole in her study ceiling.

The Fire Service in Tauranga reported trees and powerlines down, while further south, near Opotiki, the high winds blew roofing iron off a house.

A fierce storm also brought snow to low levels throughout the South Island on Wednesday night.

In Queenstown, weather forecaster David Crow said the snowfall was the heaviest and lowest for November in 45 years of record-keeping.

Arthurs Point, north of Queenstown, had 8cm of snow and Arrowtown got 5cm.

It was the most snow Arthurs Point had received in one dump this year, Mr Crow said.

The MetService said the weather would improve today, but showers were expected to return to western parts of both main islands tomorrow and on Sunday.

Eastern parts of the country would be fine over the weekend.

- Additional reporting Juliet Rowan, OTAGO DAILY TIMES