Comalco, which owns 79% of the Tiwai Pt aluminium smelter, accounts for about 15% of New Zealand’s electricity demand. It is urging a disbanding of the ‘vertical integration’ of the three state-owned power companies, Meridian, Genesis and Mighty River Power.

The three companies, which rely on hydro power for the majority of their generation, made healthy profits during the recent power crisis in spite of reduced generation from hydro reservoirs.