Electricity generator and retailer Contact Energy says generation and prices fell in October.
The listed firm says production fell 13% to 730 megawatts in the month compared with the same month a year earlier.
Prices slipped from $44.83 a megawatt hour to $32.50 a megawatt hour.
The number of customers is down 8% to 478,500, but Contact says it has picked up extra customers in recent months.