Contact Energy has been fined $245,000 for misleading customers in a 2017 fuel promotion.
The company, the country's second-largest energy retailer, pleaded guilty in the Wellington District Court and was convicted on seven charges under the Fair Trading Act 1986.
They related to false or misleading representations it made when it launched Fuel Rewards Plans, which offered fuel discounts with the AA Smartfuel rewards scheme, in April 2017.
The scheme replaced the firm's involvement in the Fly Buys loyalty scheme and offered discounts ranging from 10 to 50 cents per litre every month. Customers joining the one-year Fuel Rewards plan, which offered a 30-cent discount, could save up to $180 a year, the company said at the time.
The Commerce Commission, which brought the prosecution, said Contact's advertising failed to adequately disclose key information, including that the discount could be redeemed on only one fill per month and only up to a maximum of 50 litres.