The country's biggest energy retailer, Genesis Energy, has posted an annual profit drop of 53 percent, though the result exceeded its forecast.
The state-controlled company, which was partially floated in April, lost 3 percent of its customers in the year to the end of June.
Net profit was just over $49 million for the year-ended June while revenue fell, also by 53 percent, to a little more than $2 billion.
The chair of Genesis, Dame Jenny Shipley, said the company had been operating in a highly competitive enivironment, with many niche retail operators offering aggressive pricing and bundling options.
She said the 'What's My Number' campaign has also encouraged switching.
Other factors have included lower demand for power because of above-average temperatures and more efficient household use. Wholesale electricity prices also declined.
Dame Jenny said one of the highlights of the year was the completion of the Tekapo Canal project, which was completed under-budget and ahead of schedule.
Genesis will pay a final dividend of 6.6 cents a share.