Green co-leader Russel Norman indicated he and co-leader Metiria Turei may be happy with being senior ministers in a Labour-led government, which would open the way for Mr Peters to become deputy prime minister in a coalition government led by Labour leader David Cunliffe.
Mr Peters has made it clear in the past he does not favour working with the Greens, the Maori Party or Internet Mana.
Mr Cunliffe has already ruled out working with either the Maori Party or Internet Mana in a formal coalition arrangement but on current polling, he would need their support in confidence and supply to form a government.
And Mr Peters told about 100 people in Invercargill he was prepared to spend some money saving one of Southland's most prominent industries, the Tiwai Point aluminium smelter - the future of which is under review by owner Australian-listed Rio Tinto.
Mr Peters did not rule out a direct government investment in the smelter, if it was in the national interest.
''If gaining a shareholding in Tiwai Point retains worthwhile economic benefits for this region and New Zealand, we are open to that.
''We have already lost far too much of the manufacturing base under National and that makes us more vulnerable to an economic shock,'' he said.
At the top of the country, Labour leader David Cunliffe was promising to set up a sovereign investment fund of $100 million, funded by dividends in privatised assets and by new royalty payments from oil and gas, to perhaps buy back some of the assets sold by the National-led Government.
A KiwiShare would be created for every SOE and mixed ownership model company to protect the assets for future generations, he said.
Labour has already promised to reopen the Dunedin Hillside Workshops, at some considerable cost.
Mr Peters said yesterday NZ First would impose strict controls over foreign ownership in the areas of land, housing and strategic business assets.
''That means NZ First will stop the losses and begin buying back our country. We will reverse the wholesale sell-off of our farms by implementing a buy-back programme using our own KiwiFund scheme.''
NZ First would also collect comprehensive information on foreign ownership of land for the first time in New Zealand. National had deliberately avoided collecting data, so it could mislead and confuse the public, he said.
However, it was Dr Norman's comments on TV One's Q+A programme that were telling.
NZ First is polling well above the 5% threshold for returning to Parliament and the Greens are aiming for 15%, as both parties watch Labour struggle in the mid-20% range of support.
Dr Norman told interviewer Susan Wood: ''We are absolutely focused on getting good policies. So having good senior ministerial positions - whatever they may be - will be the way we get through''. And becoming finance minister was still on the table.
''The reason why we said what we said is the largest party gets to be the prime minister - fair enough. Everything else is on the table and it's got to be proportional according to the votes you get. We're a democracy; that should be the determining factor.''
Asked what was on the table in terms of portfolios, Mrs Turei said all of the social portfolios.
Neither Dr Norman nor Mrs Turei would be drawn on what it would mean for the Greens to become the major opposition party. Dr Norman said he did not think it would happen before election day, ''as great as we are''.
