Budgeting services are reporting an upsurge in the number of people with problems paying their power bills.
In Dunedin, the city's Budget Advisory Service co-ordinator Shirley Woodrow says power bills of $700 or more a month are not unusual. She says the situation is the worst she's seen in 18 years.
The Federation of Family Budgeting Services says in Wellington, people face power bills of more than $400 a month and many are in arrears.
The latest Energy Outlook from the Ministry of Economic Development forecasts a rise in wholesale power prices of 40% over the next two decades.
The wholesale price makes up about one third of the retail price, which will be affected by the rise.
The research concludes power demand is growing by 1.8% a year but this will drop to 1.5% annually, by 2030.
Energy Minister Gerry Brownlee says proposals are due before Parliament by Christmas which will help ease power prices.