Unison has begun restoring power to their 16,000 customers left without power in Taupō after a massive outage this morning.
Unison spokesman Danny Gough said they were continuing to work closely with Transpower to restore power as soon as possible.
"Unfortunately, at this stage there is no confirmed ETA for restoration and customers are advised to be prepared for an extended period without power."
Taupo District Council have asked people to conserve water as the pumps were running on generator power and were not operating as efficiently as usual.
Gough said Transpower had lost supply to Taupō at their Wairakei substation grid exit point about 8.40am.
"Unison has been advised by Transpower they are investigating an issue relating to the 33kV switchboard at their Wairakei substation. They will provide us with an update as soon as they have completed their inspection"
Truspower said on their Facebook page at 11.40am their crews were currently working as fast as they are safely able to restore power to the area.
"We apologise for the continued inconvenience and will update this page as we have more information, including estimated restoration times."
Earlier Gough said both transformers that supplied the main Taupō area had been tripped out.
"We understand it's frustrating for people on a busy Monday morning. We will be working to get power back up safely soon," he said.
Gough said approximately 16,000 customers were without power across the wider Taupo region.
"We have done what we can in terms of supplying off other feeders from our network. However, you can say a large swath of Taupō is without power at the moment.
"Certainly the main urban and populated areas are without power and some of the rural supply."
-More to come.