"With this in mind, the Government has been in contact with Pacific Aluminium's international parent company Rio Tinto this week to discuss helping to bridge the gap in their positions over the short to medium term, if this could be of assistance in concluding an agreement.
"In the meantime, we understand Meridian's existing contract with Pacific Aluminium remains in place at least until 1 January 2016 with significant financial and other obligations beyond that."
Ryall added that "all relevant information - including about the smelter electricity contract - will be reflected in the Mighty River Power offer document which is currently being finalised".
Labour Leader David Shearer said this morning's developments meant the National Government "must pull the plug on the Mighty River Power sale with massive uncertainty now surrounding Meridian's supply deal with Rio Tinto".
"The electricity market has been thrown into upheaval by Meridian's statement today" he said.
"If Mighty River Power is sold in May it risks turning into a fire sale with investors likely to demand a risk premium."
"There is simply no way that the Government should sell a major electricity supplier like Mighty River Power in the midst of such turmoil. The Government has been gung- ho in pushing the sales but has refused to acknowledge the risks with Tiwai Point. National must tell the public what's going on before asking them to buy shares in the electricity market."
Labour's SOE spokesman Clayton Cosgrove said Prime Minister John Key "must put aside his pride and vanity and cancel the sale. There's too much at risk".