A national grid emergency sparked a plea to the public to save power today by not charging electronic devices and only heating the room you are in as bitterly cold weather bites.
The warning came amid a fault affecting the Cook Strait cable that transfers power between the North and South islands.
Transpower said just before 8.30am that the fault was fixed and the cable had returned to "full operation".
"We are in the process of restoring controllable demand."
Transpower CEO Alison Andrew said staff had worked quickly to maintain system security during the grid emergency.
"We have a grid emergency system in place for exactly this type of situation," she said.
"Lines companies knew what was expected of them and they moved quickly to manage controllable load and reduce demand. No consumers were disconnected and the system stayed stable throughout."
Andrew thanked Kiwis who had made an effort to manage power usage.
"Fortunately we were able to resolve the issue before we had to cut additional demand which would have resulted in some consumers being disconnected. We are grateful to those New Zealanders who took action to reduce their usage."
There was now "plenty of power" available for the North Island, Andrew said.
Transpower had earlier issued a grid emergency notice, warning of a real risk of power shortages in the North Island.
The national grid operator issued the warning just before 7.30am, declaring a "North Island emergency".
"The System Operator advises there is a risk of insufficient generation and
reserve offers to meet demand," Transpower said.
The warning instructs power companies to increase generation to meet the demand, as Kiwis wake to freezing temperatures and turn on heaters.
Earlier: Public urged to 'be mindful' of electricity use today
A fault has occurred in a Cook Strait cable that transfers electricity from the South Island to the North Island.
"As a result, [we are] calling on consumers to be mindful of their electricity use this morning.
"Some power is still flowing across the cable, but a second fault could suddenly stop the flow of electricity."
Transpower spokesman Dr Stephen Jay said at this stage, people around the country would not notice any impact, as lines companies would largely be turning off controllable loads like hot water systems, which are switched on and off regularly during winter.
If the removal of controllable loads was not enough to balance the power system, Transport would need ot be ask for additional demand to be cut until the power grid is secure - meaning some households would be disconnected at some point.
Jay reiterated the message to Kiwis to conserve power this morning, in particular.
"We ask New Zealanders to be mindful of their electricity use this morning, to help us get through this situation and avoid power cuts.
"It is an unseasonable cold day, so please stay warm by continuing to heat the rooms you are using - but consider turning down the thermostat a degree or two."
Other ways people can help with the situation is to delay putting on a load of washing or using the dryer or dishwasher this morning.
Delay charging electric vehicles or electronic devices and to turn off heaters and lights you in rooms you are not using.
A dry but cloudy weather is forecast for Auckland but further south Kiwis face a frosty start and the threat of showers after a wintry blast brought unseasonable and record-breaking spring snow.
Freezing southerly winds and low-level snowfall blanketed much of the South Island and lower North Island during the last two days. Cold air moving over warmer waters near the coast also saw some scattered thunderstorms, MetService Meteorologist Amy Rossiter said.
Temperatures nationwide have dropped well below historical averages for October.
Wanaka Airport broke its record for the coldest October minimum at -3C. Dunedin and Invercargill also recorded one of their three lowest October maximum temperatures, with 7.1C and 5.9C respectively.
Christchurch also experienced its first October snowfall in more than 50 years, while the sea-level suburb of Kilbirnie in Wellington welcomed a dusting of snow.
The wider Canterbury area can expect warmer temperatures headed into the weekend, after Thursday's monumental snow blast.
The mercury dropped to 3.3C at Christchurch Airport overnight, according to MetService, while inland South Island hit much snappier lows, with -5.1C measured overnight in
Tekapo the coldest.
However, the polar blast which brought the cold snap across the country has now moved further east, following which will be a warm front to signal very early signs of summer.
Meteorologist Peter Little talked down the possibility of snow returning to Christchurch anytime soon, noting yesterday's weather event was an "unlikely" one.
"There's always a chance, but the air has to come right from the south and it has to move quickly," he said.
"There's a number of things that have to come together to get the outbreak."
Christchurch city can expect a high of 12C today, Little said, with showers in the morning and warmth returning in the afternoon. It'll be another chilly night to come, however as the city plunges to 2C overnight.
That warmth, however will continue to increase headed into the following days, as the temperature high increases to 17C on Saturday, 20C on Sunday and 21C on Monday - five degrees warmer than usual in October.
Conditions began to improve yesterday, however, bringing warmer and mostly settled spring weather - just in time for major events in the main centres this weekend.
"This will be good news for those wanting to head outdoors this weekend, whether it's with the kids for school holidays, watching the start of the Women's Rugby World Cup in Auckland, or the Cricket Tri-Series in Christchurch," Rossiter said.
Conditions should be fine for the rugby with three matches at Eden Park on Saturday, including the Black Ferns v Australia.
And morning cloud today should clear in Christchurch for the Black Caps T20 against Pakistan at Hagley Oval.
In the capital today, Wellingtonians can expect a few showers about the eastern hills in the morning with sleet down to 400m. It should become fine by the afternoon before a mostly clear weekend.
Areas of cloud and frosts could still blanket Dunedin this morning, before turning fine with strong southwesterly winds dying out by evening, MetService forecasts.
The second week of the school holidays, however, starts with rain moving up the South Island, dousing the west and south of the country before potentially moving over the North Island. MetService said there would be a mix of wet and dry weather next week.
Heavy snow warnings for parts of Southland and Otago, and a heavy snow watch for Wairarapa were lifted on Thursday afternoon as the showers eased.
Snow also fell in Dunedin, Upper Hutt, and as far north as Taupō on Wednesday and Thursday.
Rossiter said: "Snow was reported as far north as Taranaki and the Desert Road in the North Island, even down to sea level on beaches around Otago, Canterbury and Southland."
Auckland hit an unseasonably chilly 11.5C by mid-morning and didn't get much warmer, with a high of only 13C. Strong winds also reduced speeds on the Harbour Bridge.
Excitement also briefly gripped office workers in the central city with what momentarily appeared to be snow-like flurries in the afternoon.
But MetService quelled any elation of a Super City snow day.
"Considering temperatures in Auckland are in double digits, it is unlikely to be snow, there could be icy snow forming in the upper atmosphere, but as it falls it warms it turns to rain," the national meteorological service explained when queried.
The temperature in Wellington was 4.2C by 8.30am yesterday, but had a "feels like" temperature of -1C, according to MetService, and locals were advised to wear up to four layers of clothing.
Residents in Christchurch who woke to a wintry wonderland found their cars and gardens covered in snow - though not enough to have fully settled on roads.
Shane Neal, who lives in Edgeware, said this was only the second time he'd experienced snow since moving from the North Island.
He awoke early yesterday morning to find his cars and deck blanketed in snow, and said it looked stunning but the conditions "took some adjusting to".
"When I took the dogs out in the morning, I realised the deck was like a skating rink.
"It's just about adjusting your speed as you drive your car, walk around outside - it's that much more slippery."
Neal and a friend had returned last night from a trip across Burkes Pass, and he was thankful the roads remained open to complete his journey.
"You couldn't see a blade of green grass yesterday, it was a nerve-racking drive in blizzard conditions but absolutely beautiful."
It is the first time Christchurch has seen October snow since October 10, 1969. At 6.30am the temperature was officially 1.2C in the Garden City, but MetService reported it as feeling more like -4C outside with the wind chill.
The Desert Rd in the central North Island was reopened after snowfall closed the highway, one of a number of roads that were affected by the freezing temperatures.
A road snowfall warning was still in place for the Remutaka Hill road until early this morning.