Labour Party leader David Cunliffe says more and more people are having their electricity disconnected, because they can't afford to pay their power bills.
Figures from the Ministry of Business, Innovation and Employment show power use fell 3% in the year to June, and prices rose 3%: four times the rate of inflation.
Mr Cunliffe says 19,245 households had their power disconnected in the first half of this year alone.
That compares with 12,975 in the first six months of 2011, and 17,622 in the first half of 2012.
Mr Cunliffe says people are struggling to keep up with soaring costs, which is made even harder by stagnant wage growth.
He told Morning Report Labour will create the New Zealand Power Authority to use bulk buying to bring prices down and he was confident that the number of disconnections will fall as a result.
Energy Minister Simon Bridges says the situation is still better than it was under Labour. He told Morning Report there were much higher price rises under Labour.