A small group of Northlanders are waking up without power as Transpower scrambles to fix a big pylon that toppled over on Thursday.

The fallen pylon cut power to nearly 100,000 properties. Power had been restored for all but 177 as of midnight Thursday, but blackouts were expected to continue throughout Friday.

Transpower was urging everyone north of Warkworth to keep their electricity use to a minimum, especially during peak demand between 6am and 9am.

Power would not be fully restored until Friday afternoon at the earliest.

Most people in the north would also be shivering through cold showers. Lines companies Northpower and Top Energy said they had turned off the hot water for most households to stretch the limited supply as far as possible.

At least one school, Kaitaia Primary, would be shut on Friday. It said in a Facebook post that was because the electricity supply "may not be reliable or permanent".

The toppled pylon cut power to nearly 100,000 properties. Photo: Supplied / Kawakawa Electrical Ltd

Maintenance workers were at the tower when it fell, but Transpower said it was not yet known why it toppled.

Whangārei Mayor Vince Cocurullo said he was looking forward to an explanation.

"I think the big story that I've been informed so far is, no one's prepared to actually say ... officially what the cause was."

Cocurullo said Northlanders were incredibly frustrated by ongoing infrastructure failures.

State Highway 1 has been closed over the Brynderwyn hills for fourth months due to slips. Photo: Supplied/ NZTA

The pylon issue came ahead of the re-opening of State Highway 1 over the Brynderwyn hills next week. The slip-prone highway has been closed for four months for major repairs.

Further north, State Highway 1 at Mangamuka Gorge would not reopen until close to Christmas after being shut more than two years.

Far North Mayor Moko Tepania said locals were "bloody fed up".

"It's not good enough for us, for our business, for our economy and everything in between."

Northlanders were resilient, but they should not have to be, Tepania said.

Whangārei hairdresser Megan Edwards was also frustrated by the cuts, which brought her business to a "standstill".

Northland seemed particularly vulnerable to power cuts and she was sick of it, she said.

This story was originally published by RNZ