Genesis Energy says its half-year profit plunged, in part because of lower wholesale electricity margins and higher interest costs.
The publicly-owned electricity generator and retailer made $17 million in the six months to December, compared with $64.5 million in the same period a year ago.
Charges from its one-third stake in the Kupe gasfield also affected the result.
Revenue declined by 1% to $949 million and the number of customers fell slightly to 543,800.
The company will not pay a dividend to the Government for the June 2010 financial year because it needs the cash to buy the Tekapo A and B power stations from Meridian Energy as part of the mandated asset swap.
Looking ahead, Genesis expects a full-year profit of $40 million.