Unison has begun restoring power to their 16,000 customers left without power in Taupō after a massive outage this morning.
Power was expected to be back on to all homes and businesses within two hours.
Unison spokesman Danny Gough said earlier they were continuing to work closely with Transpower to restore power as soon as possible.
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."
Transpower said on its Facebook page at 11.40am crews were working as fast as they were able to restore power to the area.
"We apologise for the continued inconvenience."
Just before 6pm Transpower said in a Facebook post power had been restored to the Wairakei substation.
"Unison is currently in the process of restoring power gradually to their network, which may take up to 2 hours. We'd like to thank all of those affected for their patience and understanding as our crews worked to get power back on in the region."
At the time of the outage 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.
The outage left approximately 16,000 customers without power across the wider Taupō 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," Gough said at the time.
"Certainly the main urban and populated areas are without power and some of the rural supply."
Taupō District Council asked people to conserve water while the power was off as the pumps were running on generator power and were not operating as efficiently as usual.