Fierce winds and heavy rain lashed homes in the Auckland region overnight - uplifting roofs, toppling over shipping containers and damaging The Cloud at the waterfront.
Up to 1700 lightning strikes were recorded and emergency services were dealing with callouts from all around the city and down towards the south of Waikato.
At least one house was struck by lightning in Auckland.
Thunder, lightning and heavy rain started to pound the area from about 8pm. The NZ Fire and Emergency services responded to about 20 callouts from around Auckland and Waikato.
In downtown Auckland, part of The Cloud's awning has been torn off and left in tatters.
A spokeswoman for Regional Facilities Auckland - the Auckland Council body that manages the building - said team members were on site assessing the damage.
She said there were no bookings at The Cloud until the end of September.
Further down the road, at the Ports of Auckland, huge shipping containers looked more like Lego blocks as some had toppled over each other in the high winds.
"And the roof blew off and the doors blew in and we were all of a sudden totally exposed to this weather. It was just amazing.''
MetService meteorologist Kyle Lee said they received reports of tornadoes in northern parts of the Waikato and southern parts of Auckland overnight.
"There was a lot of attention around the front [weather system] that went across the North Island yesterday evening - plenty of lightning strikes along the front and pretty strong winds experienced from much of the top end of the North Island.
Never heard thunder like this - rolling for 20secs, very high altitude, all across the sky over the Kaipara. The weather gods must be grumpy as. @WeatherWatchNZ pic.twitter.com/u7hmxOxDIf
"It looks like there was some significant damage to a few houses and very possible we would've got a tornado or funnel cloud reaching the ground there for a brief period."
That front has since gone over and past the North Island and things are much quieter now, he said.
"We've only had a few showers for much of the western parts of the North Island and the story for today is basically the South Island should see an easing trend in the weather."
Aucklanders can expect a few showers this morning. These will become more frequent from this afternoon and there is a possibility of squally thunderstorms and hail.
Northwesterly winds are also on the cards and will be stronger in exposed parts of the city. A high of 16C is forecast and an overnight low of 10C.
Northland to Kāpiti - including the Coromandel, Bay of Plenty and the central high country - can expect periods of rain or showers today; some heavy with squally thunderstorms and hail.
Those in Gisborne and Hawke's Bay and expect fine weather. Gisborne has a high of 17C and overnight low of 8C.
In Wairarapa, Wellington, Marlborough and Nelson, a few showers are forecast this morning and rain this afternoon. Those in Wellington are in for a 12C high and overnight low of 6C.
There will also be a few showers in Buller and Westland; clearing from the south.
It will be mostly fine in Canterbury and eastern Otago and cloudy periods - with the odd shower - are forecast for the remainder of Otago and also in Southland and Fiordland.
Anyone in the Chatham Islands can expect a cloudy day with a few showers.