The average Hawke's Bay/Wairarapa power bill jumped more than $108 in the last year - $36 above the national average rise.
Grey Power warns the latest price increases will make life even tougher for local residents struggling on fixed income pensions.
The Ministry of Business, Innovation and Employment's Quarterly Survey of Domestic Power Prices shows in the 12 months to August 15, the average national power bill rose $72 - a 3.3 per cent increase.
However, the average power bill in Hawke's Bay and Wairarapa rose $108.08 in the last year - a 4.8 per cent increase.
Hawke's Bay TrustPower customers with Unison lines company suffered the biggest price increase of $156 - represented a 7.4 per cent increase in retail power costs from August 2012. This included a $104 increase in lines charges.
At the other end of the spectrum, Contact Energy customers with Scanpower lines company and Contact Energy customers with Centralines lines company both enjoyed a $2 decrease in power prices.
This was despite $82 and $91 increases in respective lines charges.
The study, which relied on Electricity Authority data, was based on an average household using 8000kWh per annum - close to the nationwide average residential consumption.
The general increase in electricity costs comes at a time when many Hawke's Bay residents are struggling to make ends meet.
According to the New Zealand Federation of Budgeting services, 4731 Hawke's Bay and Poverty Bay residents sought budgeting advice in the year to June. The average client was was carrying about $22,100 in debt.
Grey Power has negotiated a cheaper power deal for its 64,000 national members by forming Grey Power Electricity, in partnership with Pulse Energy - the parent company to Just Energy.
The deal, launched in September, gives Grey Power members access to low cost power and easy-to-read bills.
Hastings Grey Power secretary Marie Dunningham said pensioners struggling to cope with rising power bills were trying to live in cold houses.
"Looking at the older person's health - we know that cold houses become damp houses.
"We think there is no reason for the prices to be so high. 20,000 people have had their power cut off this year because they can't pay their bill."
Despite having an insulated house, using a fire for heating, washing with cold water and not using the heater during the day, Mrs Dunningham said her own power bill was $204 last month - for just two people.
"We're from a generation that was told by our daddies to 'turn out the bloody light'. So we don't waste electricity."
There was no reason for Hawke's Bay's prices to be so much higher than the national average, she said.
However, the new Grey Power electricity deal would help save money, and membership applications in Hawke's Bay had already surged since it was announced.
Electricity Authority data shows 19,245 households had their power disconnected in the first half of this year alone.
'That equates to 106 households having their power cut off every day, or four every hour," Labour leader David Cunliffe said.
Meanwhile, Energy Minister Simon Bridges has come under fire , accused of burying bad news about rising power prices for the previous quarter.
In the three months to May the cost of power for the average household rose by 2.2 per cent, adding $50 to the annual bill.