Northlanders overpaid for power by more than $11 million last year, according to the Electricity Authority.
A new report on the performance of the residential electricity market in 2015 showed Northlanders could have saved $11,565,137 - or $160 per household - last year by switching to the cheapest deal available.
Maureen Gwillim, of Whangarei Budgeting Service, said people could make sure they were getting the best electricity deal available by visiting the websites www.powerswitch.co.nz or www.whatsmynumber.org.nz, or asking budget advisers or the Citizen's Advice Bureau for help.
They should also look for power-saving tips. Old heaters could use up power, as could hot taps left running.
The budgeting service referred clients to Healthy Homes Tai Tokerau for free home insulation.
Ms Gwillim said power costs were one of the big budgeting issues facing those who came to the service, particularly in winter, along with food and housing costs. Sometimes the clients didn't ask for help until they had received disconnection notices.
Work and Income could help those with power debt and with threatened disconnections, especially if there were children in the household.
People with medical conditions should inform their power company and it would be noted on their records.
Ms Gwillim said many clients found it difficult to understand their power accounts and some didn't read them. The budgeting service encouraged them to pay by direct debit and make sure they had enough funds to do so.
The service often phoned power companies on the client's behalf to ask for smooth-pay or other payment options to be put in place, said Ms Gwillim.
New Zealand households overpaid for power by more than $300 million in 2015 by not switching to the cheapest electricity deal available, according to the Electricity Authority.
Bay of Plenty households stood to save the most at an average of $331 per household.
The lowest average savings were in Hawke's Bay, at $135 per household.
The report showed smaller independent retailers were serving nearly 80,000 customers in 2015, an increase of 12 per cent during the year.
Head of Powershop Mark Soper said smaller retailers were having a hugely positive effect on the market for consumers, driving price competition and reducing market concentration across the country.
Data from the Ministry of Business, Innovation and Employment showed the average residential cost per unit of electricity in the year to March was 1.7 per cent lower than in the previous year.
"Despite lower prices, too many households are still overpaying for power by hundreds of dollars by not switching to the best deal available," said Mr Soper.
Northland had some of the highest power prices in the country because of its distance from conventional power sources.
Energy saving tips:
* Save on hot water: Unless your clothes are exceptionally dirty, change the water temperature to cold on your washing machine. A hot wash uses 90 per cent more electricity than a cold wash.
* Compare electricity suppliers: Compare electricity supplier rates to ensure you are getting the best deal. Determining the best deal for you doesn't have to be difficult.
* There are websites, which can help you shop around and make comparisons.
* Turn off appliances when not in use: Appliances on standby draw power. Save up to $100 a year by switching off any unused appliances.