Power companies say consumers are reaping the benefits of the most competitive electricity market in 10 years.
Figures from the Ministry of Economic Development show power prices rose by an average of just 2% percent in the year to November 2009.
Between 2000 and 2008 prices lifted by more than 70%.
The ministry's latest quarterly survey also shows that 25,000 customers switched suppliers in each of the final three months of last year.
Mighty River Power chief executive Doug Heffernan says the figures reflect fierce competition by power companies for customers.
Mercury Energy, owned by Mighty River Power, gained almost 11,000 thousand customers over the period.
Mr Heffernan says generating capacity has also increased, allowing companies to contain prices.
Trustpower says it is unsustainable for state-owned power companies to be selling power below cost price.
"Contact (Energy) have been out there saying that the current price that it's being sold for by some of the retailers at the moment doesn't even recover the cost of generation - they are dead right," he says.
