Company spokesman Richard Gordon said nearly two years had passed since Genesis Energy reviewed its Rotorua prices.
"In Rotorua we hadn't had a price change for 21 months.
"Basically, it was a catch up and a large amount of the increase was driven by increases in network charges."
Everyday business costs and price changes to wholesale energy also contributed to the price change, Mr Gordon said.
Rotorua's largest energy provider - TrustPower - increased prices by $131 for the period, affecting 30 per cent of the region's power consumers.
Meridian Energy customers experienced the smallest hike in power charges ($76).
Powershop chief executive Ari Sargent said energy companies' price increases were mainly due to higher transmission charges and more expensive retail costs.
He expected power prices to edge higher next year as costs associated with the national power grid update filtered through to consumers.
"On average, I think most people would expect to see relatively flat prices, maybe a slight increase," Mr Sargent said.
"You expect from an end user customer point of view that most households should pay similar to what they're paying this year.
"They shouldn't be expecting a large increase in most cases."
Households in the King Country were least affected by power hikes - average bills rose $28 in the past year.
Far North residents were slammed with the largest increases, with average power prices jumping $306.
In November, 29,246 customers switched power companies in New Zealand, according to the Electricity Authority. Over 1800 were from the Bay of Plenty region, which includes Rotorua.
Mr Sargent said "timing" played a large role in price changes.
Power companies decided for themselves when to pass increases in lines charges on to their customers, he said.
"About 90 per cent of what a customer pays is fixed either through ... the wholesale energy costs or transmission and distribution charges."
Customer servicing costs, the profit margin set by power companies and GST made up the rest, Mr Sargent said.
