The Electricity Authority says historically since the 1970s, consumers did not pay enough for their electricity.
The authority has released a report breaking down electricity industry costs since 1974, looking at different groups of consumers and comparing the costs with the charges paid by these groups.
The analysis found that, historically, commercial consumers have paid a high proportion of the costs to supply them, whereas households paid a low proportion until the 1990s.
Rises to household electricity prices in the 2000s reflect increased fuel costs, a hike in GST in 2010, and recent increases in transmission and distribution charges.
The review was started partly in response to over-charging claims from an energy analyst Geoff Bertram, and in the wake of Labour and the Greens announcing plans to set up a central power buyer if elected this year.
Electricity Authority chief executive Carl Hansen says electricity charges were far below the cost of supply for many decades.
He says the analysis does not support claims that consumers have been overcharged for the last 30 years or so, nor does it support claims that past generation investments have been paid for by previous charges.
Mr Hansen says current charges are almost in line with the costs that were actually incurred to supply electricity.
