The biggest user of electricity in New Zealand is still affected by a power shortage last winter.
The New Zealand Aluminium Smelter in Bluff is still not operating at full capacity and says it will be some time before it is fully back on line.
The smelter cut production by 10% in May, when South Island hydro lakes were at low levels and nation-wide power savings were encouraged.
General manager Paul Hemburrow wants a better way to ensure both big users of electricity and domestic consumers have guarantees of supply in future.
He says there were no job cuts, but the long term viability of the smelter relies on a secure flow of electricty.
A review of the situation this winter by the Electricity Commission is due in December.
The Major Electricity Users Group hopes the commission will look at how the power companies optimise their supply options.
Executive director Ralph Matthes says this time of the year is probably more crucial than any other, as the hydro lakes are replenished.