The Green Party yesterday announced its support, leaving NZ First to announce what concessions it has wrung from the Government in return for its backing.
Without the support of the seven NZ First MPs, along with the six Greens, the legislation cannot proceed.
Prime Minister Helen Clark, who has made no secret that this is cornerstone legislation for her, yesterday said talks with Mr Peters had been positive.
"I never want to pre-empt positions that parties may take. But he and his party have been very constructively engaged with us for a long period of time around the scheme, so we are just carrying on those talks."
Mr Peters said he could not say what his caucus would decide to do.
Labour is determined to pass the Climate Change (Emissions Trading and Renewable Preference) Bill before Parliament rises before the election, and Miss Clark appears confident she will have the numbers.
The Greens had seemed reluctant to back the scheme, but reached a consensus just after midday.
Co-leader Jeanette Fitzsimons said the caucus had decided the substantial changes they had won justified voting for it, but she still had mixed feelings.
"It was the right thing to do. It was a difficult decision because we do not believe that emissions trading, in itself, will do enough to reduce emissions."
Mr Peters was smiling yesterday after an apparent victory over his parliamentary nemesis, Act New Zealand leader Rodney Hide.
Mr Hide attempted to detail allegations in the House that NZ First was "paid off" by Simunovich Fisheries to stop Mr Peters making corruption claims against it.
The allegations, made under parliamentary privilege, referred to the company at the centre of a 2003 parliamentary committee inquiry into the allocation of quota for the crustacean species scampi.
About that time, Mr Peters accused the company of corrupt behaviour, but later recanted, saying the claims did not stand up to scrutiny.
The committee subsequently cleared the company of wrongdoing.
In 2004, when Mr Peters was asked if Simunovich Fisheries had donated any money to NZ First, he replied: "I'm saying no."
This month he refused to repeat the denial in Parliament.
Mr Peters objected to Mr Hide's efforts to again raise the matter during question time yesterday on the basis the matter was part of a defamation case against TVNZ and Radio New Zealand and therefore sub judice.
"What he is saying is baseless and the subject of a serious defamation case," Mr Peters said.
Speaker Margaret Wilson said she was obliged to take Mr Peters' word, but would look into the matter and there were consequences for MPs who misled the House.
That did not stop Mr Hide attempting to ask further questions - eventually leading to Ms Wilson ordering him from the chamber.
Mr Peters later attempted to interject, appearing to suggest NZ First may have received cheques from individuals or groups which were never cashed.
"If there was a subsequent series of cheques, paid some substantial time later, despite the fact that there was an inquiry in this house that concerned a business and, here's the relevant point, those cheques were never cashed."
Mr Peters was then cut off by Ms Wilson on the basis that Mr Peters himself had claimed the matter was sub judice.
