Power won't be restored until at least the early evening after a massive outage in the Taupo area.
Unison spokesman Danny Gough said around 16,000 customers had been affected and it would be several more hours until power was restored.
"It will be at least early evening until we have full restoration. There has been a fault with a Transpower transformer at the Wairakei grid exit point."
Gough said Unison was doing all it could and there was 'great urgency'.