A new way of monitoring electricity prices - which calculates what people are actually paying for their power - shows consumers faced a 2.3 per cent hike in the past year.
Energy and Resources Minister Simon Bridges says the figure is the lowest annual price hike since 2001. But opposition parties say the Government has failed those on fixed incomes who are struggling to heat their homes.
"Discounts and other benefits from retailers are becoming the new norm in an increasingly competitive electricity market," Mr Bridges said.
"The new data captures what consumers have actually paid for their power - rather than the advertised price."
That included prompt payment discounts and other special offers.
The new power price data was put out by the Ministry of Business, Innovation and Employment for the year ending March. The information included the quarterly survey of domestic electricity prices for June, which included April price increases.
The documents show the 2.3 per cent hike was on top of a 6.7 per cent increase in lines company charges.
The energy component - subject to competition by power companies - dipped 0.7 per cent.
Mr Bridges said the figures showed National's power sector reforms were working for consumers.
Consumers could save, on average, $155 a year by switching power retailers.
But others warn that power prices have still outpaced inflation, hurting low-income families.
Consumer NZ chief executive Sue Chetwin said many New Zealanders continued to struggle with price hikes across all aspects of their lives, including other household bills, food and higher petrol prices.
"It's still quite hard, particularly for those in the lower socio-economic group, because electricity only makes up one part of the cost increases they're facing."
Mangere Budgeting Services chief Darryl Evans said it was "rubbish" to highlight the electricity price increase as being the lowest in years.
"You tell that to the families who are struggling and sitting in a cold house tonight - afraid of turning on the power because they're afraid of getting a large bill."
Both the Green Party and Labour said the National Government was failing Kiwi families.
"Power prices in New Zealand have risen above inflation, which has left many households struggling to pay their bills," Greens energy spokesman Gareth Hughes said.
Ms Chetwin said that as the weather continued to get colder, they expected more people to visit Consumer NZ's PowerSwitch site; designed to help people find the best deals for gas and electricity.
annual price change in electricity, across all of New Zealand, in the year to March.
increase in lines charges for the June quarter.
decrease in energy charges for the June quarter.
$155 a year
Electricity Authority figures show consumers can save, on average, $155 a year by switching power retailers.