An energy lobby group says an independent inquiry is needed to ensure electricity prices are being set at a fair rate for domestic consumers.
The Domestic Energy Users' Network says domestic prices have risen 5% above inflation, compared to 1.5% for commercial electricity prices and 3% for industrial groups.
It says growth in demand does not justify the domestic increase, as demand from commercial and industrial users has grown more than twice as fast.
An analyst for the group, Molly Melhuish says an independent inquiry into the electricity industry is needed.
She says the current system is allowing domestic prices to rise by much more than commercial and industrial ones.
Major Electricity Users Group executive director Ralph Matthes has not seen the figures quoted by the lobby group, but says his group also supports an independent inquiry into pricing.
However he says the inquiry would have to include wholesale prices and the role of the Electricity Commission.