New Plymouth-based Powerco has about 400,000 customers throughout the North Island, as well as operations in Tasmania.

It is now owned by Australia's Babcock & Brown Infrastructure following a $680 million takeover last year. Powerco changed its balance date to conform with its new owner.

Powerco chief operating officer Richard Krogh said the rise in net profit for the longer period was drivwen by steady income from its New Zealand power networks and new revenue from a gas project in Tasmania.

"The main focus for the coming year will be on further consolidation and improvement of our operations, capturing organic growth opportunities, and dealing with a range of industry issues," Krogh said.

Total revenue for the period of $444.5 was 36% higher than for the previous 12 months, when annual profit was $27.6 million.