Tiwai Point aluminium smelter has agreed to lower its consumption of electricity, as a lack of rain has placed pressure on hydro generation.
The smelter, which consumes about 13 percent of the country's power, has reached an agreement with Meridian Energy to reduce its usage by up to 30.5 MWh (megawatt hours) until the end of May.
The smelter has a supply contract with Meridian to provide it with cheap power until 2024.
The decision comes as a lack of rain, falling hydro lake storage and a shortage of natural gas has seen wholesale power prices spike in recent weeks.
The high prices have driven up the costs for big manufacturing companies and even forced the temporary closure of the Norske Skog paper mill in Kawerau, leading some to question if the smelter would have to reduce to its load.
The deal will see the smelter compensated for any load it decides to reduce.
However, Meridian still maintained the ability to call a "Smelter Demand Response" which allows it to recall power if the dry year trigger level is reached.