Mighty River Power does not expect to repeat its record profit this financial year.
The State-owned electricity generator and retailer's profit rose 43% to $159.6 million in the year to June, as it took wholesale generation business and customers from Contact Energy, which saw profit fall by 50% over the same period.
Other operators had to buy energy from Mighty River to make up for low levels in South Island hydro lakes.
Chief executive Doug Heffernan says that's unlikely to happen again this year as it will be hard to repeat the result.
He says the company's profit increase almost matched Contact's decrease.
Mighty River will pay the Government a dividend of $80 million, plus a special dividend of $150 million.