Last week the National Party's new energy spokesman, Roger Sowry, said people should be "outraged" that the government put them through a rigorous autumn power savings campaign, while later getting a bigger dividend from the government-owned trio of Genesis Power, Mighty River Power and Meridian Energy.

During the past month these power companies have announced increased annual profits and dividends, meaning the government has received a total of $NZ269 million, up more than $NZ16 million, despite the three-month autumn power "crisis" when consumers were urged to cut back usage by 10%.

However, a Forsyth Barr report says any calls for regulation due to "perceived excess profitability" has little merit, with the book value of the three State-owned companies still well below market values.

That means published returns are overstated, providing a disincentive to increase profits through higher power prices to retail customers, Forsyth Barr says, though retail electricity prices are too low and need to rise.

Average retail prices in New Zealand range from about 15.5 cents per unit from Empower (now owned by Contact), to just more than 17 cents a unit from listed Tauranga-based company TrustPower.

Forsyth Barr said the key value share price drivers would be higher wholesale and retail power prices.

Forsyth Barr said it believed the implied valuation of Contact Energy and TrustPower was $NZ1.5 million a megawatt and $NZ1.8 million a megawatt respectively; while Meridian, now the biggest power company with over $NZ4 billion in assets, was valued at around $NZ1.2 million a megawatt, with Mighty River about $900,000.

Meridian's annual profit equalled a 4.8% return on equity, compared with Contact's 5.1% and TrustPower's 8.2%.