The MP whose pivotal vote will ensure that the Government can partially privatise more state assets is confident the shares will stay in New Zealand ownership.
The Cabinet has agreed in principle to sell up to 49% of state-owned energy companies Genesis Energy, Meridian Energy, Mighty River Power and Solid Energy and reduce the Crown's 76% shareholding in Air New Zealand.
On Thursday, the Government confirmed that the first company to go on the block will be Mighty River Power.
The Government is promising to retain a majority share of 51% of the state-owned companies, saying New Zealand investors will be at the front of the queue to buy shares.
Finance Minister Bill English says New Zealand investors will be given priority, but that will not be put into law.
The Green and Labour parties say most of those shares will eventually end up overseas-owned.
Greens co-leader Russel Norman says the Government can't guarantee retaining 51% of the shares unless it and future Governments are prepared to buy majority stakes in any future share issues to raise capital.
Dr Norman expects that is unlikely and says the majority shareholding will be diluted.
Labour spokesperson for State Owned Enterprises, Clayton Cosgrove, says there is no way to stop the shares from being sold on to overseas investors.
But United Future leader Peter Dunne - whose single vote will allow the Government to pursue its plan - rejects that.
Mr Dunne says there are plenty of Maori, KiwiSaver and super-fund investors who would buy shares for the long-term.
Sale offer likely in mid-2012 - English
Finance Minister Bill English says Mighty River Power is ready to go to market and will be prepared for an initial public offering probably in the second half of next year, subject to market conditions.
Mr English says the partial sale of the other assets will be spread over the next three years, depending on market conditions and company circumstances.
Both Mr English and State-Owned Enterprises Minister Tony Ryall believe that even if there is continuing international economic uncertainty, if anything, it will increase domestic interest in partial share floats.
Mr Ryall told Checkpoint the government had a number of options to ensure it retained contol of the allocation of shares and ensuring ordinary people who want to invest in these businesses were at the front of the queue.
He said the choice of option would be worked through as part of the due diligence process.
More details about the structure and timing of the sale programme, including the initial public offering for Mighty River Power, will be issued early next year.