Nearly 1170 Genesis Energy customers with the Centralines lines company experienced the biggest hike in local prices ($254).
Part of this rise was due to a $23 increase in lines charges.
Hastings Budget Advisory Service co-ordinator Greta Wham said many clients needed help managing their power bills.
"Beneficiaries especially, people who would like a job but can't find one, find it very difficult to manage.
"And one of the ways they try and make their budget balance is by cutting down on food, because often that's the only expendable item in their budget," Mrs Wham said.
Nova Energy had the lowest increase in retail charges locally, with customers experiencing no rise during the 12-month period.
In Christchurch, nearly 20,000 Mercury Energy customers were slammed with an average power bill increase of $423 for the country's steepest hike for the period.
The jump was partly due to a $60 increase in Orion NZ lines charges.
Further south, 600 lucky Otago residents saw a drop of $104 in their power bills. The Trust Power customers were with the Network Waitaki lines company.
New Zealand's Electricity Authority said competition between power retailers was key in keeping prices down.
In the past four years, four independent retailers had entered the market, with four others considering a entrance, chief executive Carl Hansen said.
Consumer NZ recommended customers shop around to ensure they received the cheapest rates.
People should compare plans across different power companies, chief executive Sue Chetwin said.
"If you are not [getting the best power rate] then ring your retailer and say, 'I can get cheaper power elsewhere'."
