Auckland lines company Vector has been fined $3.5 million for having too many power outages.
"Auckland consumers have a right to expect a good quality of service from their lines company and Vector failed to deliver it," said Commerce Commission deputy chair Sue Begg.
Vector has to "comply with… regulations regarding the maximum revenue it can collect and the minimum standards of quality it must deliver", and has failed to meet the standards five years in a row.
"Vector is the largest electricity distribution business in New Zealand, having at least 540,000 or more customers at the relevant time," said Justice Duffy. "Those customers are likely to have suffered losses… A significant penalty must be imposed to act as an effective deterrent to Vector and other distributors."
Vector is majority-owned by the Auckland Energy Consumer Trust, whose beneficiaries are electricity customers in parts of Auckland, Manukau and Papakura.
The penalty could have been much larger - it was reduced by 35 percent as Vector didn't challenge the ruling.
The Commerce Act anyone allows who's suffered losses or damages due to a power outage to bring a claim for compensation against Vector within 12 months.