The Green Party says a report on low income households showing families cutting food bills to afford prepay metering for electricity is appalling.
The Otago University study published in the New Zealand Medical Journal covers 2010 and 2011, and says three out of five households with children reported cutting back on groceries to pay for electricity.
The report concludes about 28,000 prepay customers pay 3% to 38% more per unit of electricity.
It says the likelihood of households with children having their power supply disconnected is almost 60%.
Greens energy spokesperson Gareth Hughes says it is a sad reality for many struggling families that are going without food and heat during winter because of the price of power.