The power cut is thought to have originated at a Wairakei substation, close to Wairakei geothermal power station.

Power is being restored to households in Taupō after an outage which lasted most of the day.

Transpower said at 6pm that crews had restored power to Wairakei substation - but it could be some time before everyone was back on the grid.

Some 16,000 customers around the greater Taupō region were without power, which Unison lines company's Danny Gough said originated with a fault at the Wairakei substation at 8.40am.

FACEBOOK/TRANSPOWER Transpower said at 8.50am that crews were investigating the cause of a power cut across Taupo.

In a statement at 6pm, Transpower said the outage was down to an electrical equipment fault which occurred on one of the feeders that supply Unison.

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*Substation issue causes Taupō area power cut

"We estimate it will take some time for Unison to restore power to individuals and businesses in affected areas," a spokesperson said.

ROBERT STEVEN Transpower said at 8.50am that crews were investigating the cause of a power cut across Taupo.

"There is never a good time for communities to be without power, and we apologise for the inconvenience. Our priority is restoring power supply to the wider Taupō region as soon, and as safely, as possible."

Unison said it was working to "progressively restore power to homes and businesses in the region" but it would "take up to two hours to have everyone's power back on".

Plans had earlier been put in place to set up emergency centres in Taupō if the power was not restored for everyone. Taupō Mayor David Trewavas said council had moved to help those who needed it if the situation continued.

"We've got a plan in place if it is necessary to go to that [emergency centres]," said Trewavas.

Trewavas said it was disappointing to have the power cut in what he said was a repeat of an incident a year ago, especially for local retailers. "They've lost a day's trading," he said.

His comments were echoed by Taupō Business Chamber vice president Penny Lyons, who said that almost all CBD businesses' were closed.

She found one silver lining however. "If we could have chosen one day, Monday is better."

Gough said Unison was "acutely aware of the disruption that a power cut brings to customers and businesses".

"We thank everyone for their patience while we try to restore power," he said.

"We are continuing to work closely with Transpower NZ to restore power as quickly as possible, whilst not compromising safety."

For updates, Taupō customers should check Unison's Facebook page, or to call its customer service team on 0800 286 476.

Kinloch, Wairakei Village and Reporoa are without power too.

Turangi, Tokoroa, Mangakino and Whakamaru still have power.

Taupō Hospital has back-up power systems and Taupō Airport has a generators running to power guidance systems.​