It's the great Kiwi power rort, and a university researcher is about to expose all in a new book.

His research shows New Zealand power prices have surged at twice the rate of nearly every other developed country over the past 30 years.

Victoria University researcher Geoff Bertram says that means our power prices are now more than twice what they were 30 years ago, in real terms.

Residential customers were the hardest hit. "It's open season to screw anyone who can't fight back," Bertram says.


Power companies had revalued their assets and were using increases on the balance sheet to justify higher prices, he said.

Energy Minister Simon Bridges ducked the issue yesterday while spokesmen for Mighty River Power and Genesis Energy declined to comment.

But electricity industry watchdog Molly Melhuish says Bertram is bang on, and the Government is not doing enough to protect consumers. "This is the only country in which the regulator protects investors instead of consumers," she says.

Bertram's research shows most other Western nations have had little growth in power prices in recent decades.