New figures released by the Labour Party show an increase in the number of people whose power supply has been cut off because they didn't pay their electricity bill.
In answer to a written parliamentary question, Energy and Resources Minister Simon Bridges confirmed there were nearly 41,000 residential power disconnections due to non-payment last year, 10,000 more than in 2011.
Labour leader David Shearer said on Wednesday the figures back up concerns about the impact of a relentless rise in electricity prices.
In April, Labour and the Greens said if that elected in 2014 as government, they would establish a state-owned company, NZ Power, to buy electricity so it is cheaper for consumers.
Mr Shearer said power prices rose five times faster than inflation last year and it is making some people feel like they are failing because they can't afford to heat their homes properly.
"The Government's not doing anything about higher power prices, in fact (Prime Minister) John Key has said that power prices aren't too high."
Mr Shearer said the market was broken and the Government needs to intervene to bring down prices.
Greens co-leader Russel Norman says the situation is extremely serious and the Government is not doing anything about it.
"The National Party doesn't want to know and doesn't care about the situation of ordinary New Zealanders who are having their power cut off or who can't afford to heat their houses properly.
"There's actually things that we can do about it right now - NZ Power is part of it - and also the home insulation scheme. This is a problem that is solvable - it just requires the Government to care."