Lines companies, not retailers, fix faults
New Zealand splits electricity into three layers. Transpower runs the national grid, lines companies carry power from the grid to your home, and retailers bill you. When a tree comes down on your street, the lines company sends the crew.
The Commerce Commission's 2026 data lists 29 lines companies. They vary enormously: Vector has about 635,000 connections around Auckland, while small rural networks serve only a few thousand. Each runs its own outage page, usually branded as an "outage centre" or "outage map", and there's no shared national view.
Mergers matter too. Nelson Electricity became part of Network Tasman on 31 March 2026, so older links and phone numbers may be out of date.
When a single line takes out a region
Northland shows how exposed parts of the grid can be. On 20 June 2024, a transmission tower collapse cut supply points at Kaikohe, Maungatapere and Bream Bay, and about 88,000 customers lost power just after 11am. The Electricity Authority later found the causes entirely avoidable.
Auckland has had the same lesson twice. A fault at Ōtāhuhu substation in June 2006 cut power to about 230,000 customers for around six hours. In 1998, the Auckland CBD power crisis lasted about five weeks.
Storms and earthquakes
Cyclone Gabrielle was the largest recent event, with nearly 240,000 customers losing supply. Flooding at Redclyffe substation cut supply to Hawke's Bay, and Transpower declared a grid emergency. Earthquakes are a risk few other countries on this site share: after the February 2011 Christchurch quake, Orion said about 150,000 customers were still out that night.
Deliberate power cuts are rare. On 9 August 2021, about 34,000 customers lost power without warning when demand reached a record peak, and the Electricity Authority's reviews found they were disconnected unnecessarily. New Zealand's electricity was 88.5% renewable in 2025, the highest share since 1981.
A caution on national averages
The Commerce Commission's headline of 241 minutes and 2.01 interruptions for the year to March 2025 is a simple average of the 29 companies. That gives a tiny network the same weight as Vector. By our calculation, weighting by connections gives about 201 minutes and 1.71 interruptions. Company figures also exclude low-voltage faults and Transpower outages, so they understate what some households experience.