A tornado-like waterspout has ripped through central Auckland's waterfront, toppling at least one shipping container and wreaking havoc on yachts, ships and cars.
Vehicles were swept into the ocean and a yacht was struck by lightning as the storm left a trail of destruction on Monday night.
A shipping container toppled on to a car at Jellicoe Wharf near Tinley St, trapping the driver. They were tended to by emergency services and taken to hospital in a moderate condition.
Several yachts at Westhaven Marina lost their moorings and a catamaran was overturned in the turmoil.
Coastguard duty officer Hemi Manaena said the winds had caused "significant damage" to a large number of recreational vessels at Westhaven.
The Sealink Ferry also lost its mooring at Wynyard Quarter and needed to be retrieved.
"We'd like to reiterate that there's a large amount of debris in the harbour," Manaena said.
"Mariners should remain vigilant when navigating the area, especially around the Princes/ Hobson Wharf area - a shipping container has fallen into the water there."
There were reports of other containers floating in the harbour and a car had also gone into the water near the entrance to the Viaduct. Other cars were being retrieved by a tow truck.
Harbourmaster Captain Andrew Hayton said there was localised minor damage to wharves and pontoons from North Head to the Harbour Bridge.
"A 50ft catamaran has capsized at Westhaven, it took out a fuel bowser and a small amount of diesel spilled, the fuel has disappeared and there is no pollution worry," he said.
"The Harbourmaster has a couple of boats out checking wharves and recovering anything floating in the water."
Panuku Development Auckland's Kevin Lidgard said they were relieved no one was hurt around the marinas - at Westhaven, Silo and Viaduct - during last night's storm.
Workers would be out assessing the damage and cleaning up.
He said about 45 vessels were damaged or broke their moorings at Westhaven last night and there was also damage to some marina infrastructure.
"The damage at Silo and Viaduct marinas is restricted to the pontoon structure and some damage to a vehicle and Portacom that blew off the wharf.''
Lidgard said all vessels were secured overnight when it was safe to do so and there would be continued checks of all three marinas for any other damage not yet identified.
The destruction comes as thunderstorms rolled across the city on Monday night, bringing torrential rain and high winds.
Sheet lightning repeatedly lit up the Auckland sky, accompanied by claps of thunder.
MetService said around 25 lightning strikes were recorded over land in the Auckland region.
The most rain fell in West Auckland, with a record of 9.5mm in an hour, while the strongest wind gusts were in Manukau which had one gust of 89km/h.
While Auckland may feel some reprieve today, the weather trough is expected to move away to the east this morning, with a risk of thunderstorms in areas from Northland to coastal Waitomo, also Coromandel Peninsula and Bay of Plenty before dawn.
Any thunderstorms are likely to be accompanied by localised heavy rain of 10-20 mm/h, strong wind gusts of 90-100km/h and hail of 5-15mm in diameter.
A broader low risk of thunderstorms covers Taranaki, the remainder of Waitomo, Taupō and coastal parts of Gisborne, Hawke's Bay and Wairarapa also before dawn.
MetService meteorologist Sarah Haddon said the North Island was still in the showery, westerly flow today.
"For all the western areas, and spreading into the Bay of Plenty we have showery forecasts. There was a thunderstorm risks before dawn, but those thunderstorms have moved away to the east now and have eased a little bit this morning.
"But we are expecting that thunderstorm risk to return tonight, for western areas about the coast from Taranaki up to the southern part of Northland."
Haddon said the South Island was experiencing a southerly change, with showers expected in western areas.
"As that southerly change moves up the South Island, we expected it to reach Wellington late tonight. It will pretty much spread over all of the South Island, but shower activity associated with that is more confined to Otago and southwards.
"That southwest change is quite strong, there will be gales about the coast and it will feel quite cold."
Although the South Island is missing out on all the thunder, road snowfall warnings are still in place for Lewis Pass (SH7), Arthur's Pass (SH73), and Milford Road (SH94).
Dunedin is also forecast to get snow to 300m.
Tornado 'sucking up all the plants'
In Auckland, road cleaner Fine Kaufusi, 40, was on the graveyard shift at the Viaduct when it started to rain heavily late last night.
"It was around 10 o'clock. I was in my buggy on the other side. I was about to start my work when it started to rain, so I waited.
"All of a sudden I saw like a light and then a tornado - it was sucking all the plants and branches into it.
"Lucky I didn't come over here with my buggy because that would've been me sucked up," he said.
Kaufusi, of Otara, said after the tornado had passed, he and his co-workers came out to survey the damage.
"There were branches everywhere and the [construction] fences were down.
"My mate came with the compactor and just cleaned it all up.
"I'm still cleaning - still some leaves left," he laughed.
Asked if he was scared at seeing the tornado, he said: "No. In Tonga we see bigger [storms]. This was nothing."
'Too scared to open door'
However, other witnesses weren't so brave as high winds ripped through Auckland's waterfront.
"I was honestly too scared to open up the door because everything was just flying around," said an NZME employee, who lives on the Viaduct.
"Roofing is flying around and there are a lot of ambulances out there."
The witness, who was at Princess Wharf, said it looked like everyone was being evacuated.
She said there were a lot of emergency vehicles at the scene and she understood several people had been injured.
One ambulance and two ambulance Jeeps were on site. There were also four fire trucks further along the wharf.
Nearby resident Emily Cordwell described seeing a huge flash of lightning strike a yacht near Auckland's Harbour Bridge.
"As soon as it hit we just saw all these emergency services go rushing towards it. I was crazy, I've never seen anything like it."
She also watched as the storm ripped across Auckland Harbour Bridge.
"We filmed the storm from our flat on Nelson St. Suddenly it went dark and disappeared and sounded like a freight train coming through."
Henderson resident Andy Robinson in West Auckland said his property was pelted by large hailstones.
"The windows were ricocheting so hard it was like rocks being thrown. I can't see any broken panes [amazed] but cracks can form a day or so later.
"A lot larger than pea-sized, the largest were approximately golf ball sized. Certainly the largest hailstones I can remember seeing."
MetService severe weather forecaster Allister Gorman said there were all the ingredients for a tornado in Auckland.
"It could be severe gusts from the thunderstorm which happens when it collapses and all the air rushing out, it can be strong enough to blow containers over.
"There definitely was some strong winds recorded around Auckland's harbour bridge at the time.
"Temperatures dropped two or three degrees in a short time which is always a good indicator but we can't confirm it was a tornado at this stage."
Earlier, MetService issued a severe thunderstorm watch for Taranaki to Northland until midnight tonight.
It followed a wild 24 hours of weather, which saw the roofs of homes blown off in St Heliers, a house hit by lightning in West Auckland, The Cloud on Auckland's waterfront ripped to shreds and a tornado rip through properties in Taranaki.
A woman suffered a broken collar bone when the twister threw her against a wall and another woman's caravan was tipped on its side by the ferocious winds.
A few showers, mainly from afternoon. Westerlies, strong at times. High 16C / Low 10C.
Auckland: A few showers, chance of a thunderstorm this evening. Southwesterlies, strong at times. High 15C / Low 10C.
Tauranga: Fine spells and a few showers from afternoon. Westerlies. High 15C / Low 9C.
Hamilton: A few showers, more frequent from afternoon. Westerlies. High 14C / Low 8C.
New Plymouth: Fine spells and a few showers, mainly from evening with the chance of a thunderstorm. Westerlies, strengthening. High 13C / Low 10C.
Napier: Fine, but chance shower late afternoon. Northwesterlies. High 17C / Low 7C.
Wellington: A sunny day. Northwesterlies, changing southerly overnight. High 13C / Low 6C.
Nelson: Fine. Southwesterlies. High 13C / Low 6C.
Christchurch: Fine. Cloud increasing this evening as northwest breezes change to brisk, cold southwesterly. High 14C / Low 2C.
Dunedin: Fine at first. A few showers developing afternoon as northwesterlies turn strong, cold southwest. Snow to 300 metres. High 11C / Low 4C.