Several thousand properties across the North Island will spend the night without any power as Cyclone Gabrielle makes it difficult for repairs to be carried out on damaged networks.

As of 4pm today, officials warned up to 80,000 properties may face a night in the dark.

Many of them will be in Hawke's Bay and Gisborne, where Transpower declared a Grid Emergency on Tuesday morning following the flooding of the Redclyffe substation near Napier.

Transpower has warned outages for Unison and Eastland customers could last days to weeks.

The Unison and Eastland networks that distribute electricity to the region are also down as a result.

'Due to the current situation, we are not able to obtain communications from our substation, but it is likely the Redclyffe substation is underwater,” a Transpower spokesperson says in a statement.

Transpower had a helicopter on standby, but could not yet access the area.

'Until access can be gained it is hard to paint a clear picture of how long the region will be without power, but the community should be prepared to be without power for days to weeks, rather than hours,” the spokesperson says.

The Unison website showed more than 41,000 customers were affected by power outages across its network in Hawke's Bay, Rotorua and Taupō.

The company reported a 'widespread Transpower outage”, with almost 19,000 customers left without power in Hastings alone.

In a Facebook post on Monday evening, Eastland Network reported 716 customers had the power off in northern Hawke's Bay.

'There have been more power outages since our 7.30pm update, with trees and lines down, damage to poles, strong winds and flooding, right across parts of Tairāwhiti, Gisborne city, Mahia and Wairoa,” the post says.

More power outages were expected overnight.

In a statement issued on Tuesday afternoon, Powerco says 20,090 of its customers were without power, with the Coromandel, where 7433 customers were without power, being the hardest hit.

Powerco says there were also 3907 customers in Taranaki without power, 3478 in South Waikato, 3597 in the Bay of Plenty, 395 in Manawatū, 919 in Wairarapa and 361 in Whanganui.

It says 67,590 customers were impacted by the storm in the last 24 hours.

'Crews will continue to work up until 9pm tonight reconnecting customers where it is safe to do so.

'Customers not connected by that stage will unfortunately be off overnight.”

In an emailed statement, Vector spokesperson Sophie Coley says the devastating impacts of Cyclone Gabrielle had been felt across the Auckland power network.

On Tuesday, the treacherous conditions left 38,000 homes and businesses without power across its network.

Coley says Vector was not able to predict how many customers would be without power overnight.

North of Auckland, more than 20,000 Northpower customers were also facing a night without power.

Northpower spokesperson Rachen Wansbone says the cyclone had caused 'catastrophic damage to the electricity network across Kaipara and Whangarei, with further extensive damage overnight”.

'This morning we had 28,000 customers without power across the network. Now there are 26,000 who are still without any power and at least 20,000 will likely be without power for the night.

"Winds gusting to 140kph, flooding, slips, and major damage from trees through lines are making restoration attempts difficult and impossible in some situations.”

Throughout central Hawke's Bay, Centralines had 5600 customers affected by outages with 1700 households still without power.

This number was likely to increase as the wild weather continued.

In Northland, Top Energy had 43 outages with about 14,000 homes without power.

Top Energy chief executive Russell Shaw says most of the rural network had been damaged.

'Never before have we dealt with such a fluid and dynamic range of outages on our network in such a short period of time.

'The number of outages we are dealing with fluctuates as the winds change – we went from 14,000 homes off last night to under 5000 during the day yesterday, then to rise again overnight to 14,000 this morning,” he says.

Shaw says fatigue of staff has also been a concern and additional support crews have been stranded south of Whangārei due to the flooding.

A spokesperson from Waipa Networks, which covered the area around Kawhia, Waitomo and Te Awamutu, says on Tuesday morning just under 7000 customers were off the grid.

On Tuesday afternoon, Counties Energy reported 5000 properties were without power.

In an email statement, Counties Energy spokesperson Jodine Laing says the networks has been sustaining more damage as the cyclone changed direction towards the Counties area.

Elsewhere, there were 1000 properties without power in the Waikato District, Wel Energy reported on Tuesday morning.

That included 877 properties northwest of Hamilton. There were at least 1494 properties that had unplanned outages from Monday, the majority of them late at night.

In an email statement, Scanpower chief executive Lee Bettles says 240 customers were without power in the Tararua region.

'These are predominantly located in the eastern part of our network

'For access and safety reasons therefore, we are unlikely to commence repairs until tomorrow (at the earliest) and correspondingly many of the customers without power will remain so overnight.

'We will be sending engineers up in a helicopter tomorrow morning (weather permitting) to undertake an aerial survey of the damage caused,” says Bettles.

The Lines Company​, which operated in south Waikato, reported 13 outages with the number of customers affected still unknown.

So far, Wellington Electricity and Electra, the two companies operating the networks in the Wellington region and Kāpiti coast, have not reported any outages due to the cyclone.

- Federico Magrin/Stuff.