Of the 47,442 residential households in the two districts, 13,221 or 28 per cent were Genesis customers followed by 11,455 for Mercury, 10,876 for Meridian and 6494 for Contact.
In the Mid and Far North, Genesis is the fourth-biggest power retailer serving 3080 customers.
Contact is the biggest supplier then Mercury followed by Trustpower.
Meridian doesn't have any plans to review its current energy prices for about 11,000 customers in Northland.
A Genesis spokesman said the price changes were due to an annual review of its pricing which took into consideration a number of factors such as inflation, generation costs and wholesale prices.
"For our customers currently on fixed price contracts these changes won't have an impact until their existing contract ends," he said.
Under household plan, daily fixed charge for Genesis Mid and Far North customers will increase from 146 cents to 152 cents and the anytime rate from 40.20 cents to 41.98 cents per kilowatt.
For Whangarei and Kaipara customers, daily fixed charge will rise from 100 to 104 cents and the anytime rate from 28.91 to 30.21 per KW.
Ms Shortland said the impending power price rise meant an increase in living expenses for families trying to make ends meet.
She said it was not just power but petrol and rent prices have also gone up.
There was no justification for electricity charges to go up every year, she said.
"Do they really have to go up? I doubt it. It's all about profit. I don't know how families are going to keep up with another rise," she said.
In 2015, Northlanders who did not switch to the cheapest providers overpaid for power by more than $11m and New Zealand households by more than $300m.
Northland has some of the highest power prices in the country because of its distance from conventional power sources.
Last year, the Electricity Authority sought public feedback on changes to the way transmission costs are charged by Transpower, which wants to recover the full cost of its services, including $3 billion of upgrades in the North Island.
The authority has proposed multiple options, including increasing lines charges for Top Energy customers in the Far North from $155 to $421, an increase of 172 per cent, and from $300 to $560 or an 87 per cent hike for customers on the Northpower network in
Whangarei and Kaipara.
In April this year, the EA back-tracked on plans, or at least put them on hold until after the election, after a series of major errors were found.
Those errors are understood to be as fundamental as locating power stations on the wrong island and overstating the Far North's power consumption by a factor of 10.