Greens MP Adam Bandt won't support a minority coalition government, the party's NSW Senate hopeful Lee Rhiannon says.
Mr Bandt, the first Greens MP to be elected to the lower house in a general federal election, will join three independents in a likely hung parliament.
The race is now on between the major parties hoping to woo them and form government.
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Ms Rhiannon said that although she had not directly spoken to Mr Bandt since he won the seat of Melbourne on Saturday, she believed he would resist attempts by Opposition Leader Tony Abbott to curry favour with him.
"What Adam has been very clear about in the campaign (is) his concerns about how Mr Abbott has conducted himself (and) the policies of the coalition and that he wouldn't be supporting an Abbott government," she told reporters in Sydney on Sunday.
Ms Rhiannon said Mr Bandt's win was historic, calling it a "huge breakthrough" for the Greens.
The Greens also gained a major swing in Infrastructure Minister Anthony Albanese's formerly safe Labor seat of Grayndler, in Sydney's inner west.
At midday on Sunday, Labor had 46.8 per cent of the vote while the Greens - with a swing of almost seven per cent - had 25.4 per cent.
The Liberals had 24 per cent.
The Greens candidate for Grayndler, Sam Byrne, said votes would be recounted on Monday, and he was hopeful about the result, which he described as "ultra marginal".
"The Greens are not conceding defeat in the seat of Grayndler," Mr Byrne told reporters on Sunday.
"It's very close - it's gone from being one of the safest Labor seats in the country to now being on a knife edge."
Mr Byrne said the result showed a rejection of Labor's failure of leadership and policies in the area, adding that Mr Albanese would be relying on Liberal preferences to get elected.
Wilkie not ready for horse-trading
Potential federal independent MP Andrew Wilkie says he will wait for confirmation he has won a seat before he begins negotiations with either party trying to form government.
Mr Wilkie is favoured to take the Tasmanian seat of Denison from Labor, joining three other independents, Rob Oakeshott, Tony Windsor and Bob Katter, and Greens MP Adam Bandt in a likely hung parliament.
But he told reporters he was focused on the result of the poll before he started horse trading.
"I just want to get elected first," Mr Wilkie said in Hobart on Sunday.
"We may not know the result for two weeks. As soon as we know what the political landscape looks like, I need to say what I'm going to do, because it would be unfair to Australians.
"There will be a lot of pressure on me, there's a lot of pressure on me now."
He said his former membership of the Greens meant nothing.
"I am genuinely independent," Mr Wilkie said.
"I am going to put it to the Labor Party and the coalition to convince me that you can deliver stable government for three years, competent government for three years and ethical government for three years.
"I'll support whichever party can do that."
He said he had spoken briefly to Prime Minister Julia Gillard on Saturday night, and would seek to get in contact with the coalition on Sunday.
