Mighty River Power says the new financial year has started positively with customer numbers rising by 2000 but its preparation for a potential listing prevents it from giving a profit forecast.
The state-owned electricity generator and retailer, scheduled to be partially floated under the government asset sale plan, says earnings for the year to June rose 4% to $461 million, the lower end of guidance given in March.
A big fall in interest rates in the first half of the year resulted in losses on its non-cash assets, driving down net profit by 46% to $68 million - a figure that includes unrealised changes and one-off items.
The company produces more than 90% of its electricity from renewable sources and has notched up 5% growth in sales volumes and prices.
Chief executive Doug Heffernan says he can't reveal details of the year ahead because of the Financial Market Authority's rules on initial public offerings.
But he says pricing is an important part of the strategy to drive up profits.
Mr Heffernan says the company had a strong performance in the first half of the year, but hydro generation fell by 2% from the previous year due to adverse impacts in the last quarter.
Since June, inflows to competitors' South Island reservoirs have improved but remain below the historical average, while its own Waikato catchment has risen 10% compared with the same period last year.
Mr Heffernan says closure or cutbacks at the country's largest energy users, including Tiwai Point Aluminium Smelter, would have a hugh impact on the industry but Mighty River is well placed.
The company has invested $SU250 million in international geothermal developments through the GGE fund and will consider contributing further capital.
Mr Heffernan says Mighty River's international investment is a small portion of its $5.5 billion assets but is becoming more important.
The company will spent at least $6 million preparing Mighty River for public listing.
The Government will decide next week whether to go ahead with the listing this year.