He said doubts about Tiwai, which uses around 15 per cent of New Zealand's power supply, had added downward pressure to Contact's share price because of the possible damage the smelter's closure could do to the local electricity market.
Should the smelter close, wholesale power prices are likely to fall, affecting the earnings potential of all power companies including Mighty River, which the Government is now in the process of partially privatising.
Prime Minister John Key said the smelter's ultimate owner, Rio Tinto, had rejected the Government's offer to subsidise its power bill.
Last week, the Government opened discussions with Rio in a bid to broker a deal over a variation to the existing electricity contract.
But Key told Newstalk ZB's the company came back over the weekend to turn down the offer made by the Government, saying they wanted a longer term deal than the Government was prepared to offer.