Updated 10.34am: Power prices are tipped to come down this year.

The Electricity Authority has released its annual review and says it expects power prices to be flat to falling over the next 12 months.

Authority chair, Dr Brent Layton, says increased competition will help in bringing prices down.

"We've had over the last 18 months 8 new retailers set up shop. About half of those are after the household consumer."

Brent Layton says there are now 27 different electricity brands in the market.

The Electricity Authority's annual review shows medium-sized companies netted 40,000 new customers, putting pressure on the likes of Contact, Genesis, Mighty River and Meridian.

Dr Brent Layton says those big companies have lost some market share to smaller players like Nova and Trustpower.

The Electricity Authority's annual review of the electricity market shows nearly 70% of consumers were approached at least once over a two year period being encouraged to switch providers.

Dr Brent Layton says 20% of those contacted changed their provider.

He says that's the highest percentage of switching rates in the world, and that more competition in the market will help bring power prices down.

But Labour's energy spokesperson Stuart Nash says more can be done.

"I would like them to drop more than slightly. There is no doubt that there is more competition in the market, but as long as it is driving down prices."