A fault at the Kikiwa substation near St Arnaud knocked out power to almost the entire West Coast this morning.
The fault was on the national grid, Transpower said, and it was still investigating.
Supply was cut shortly before 8am and was progressively restored over the next hour and a half.
Customers on the Westpower and Buller Electricity networks were all affected, as well as Murchison.
- Greymouth Star