Bob Brown has lashed out at the Opposition's push for an early election, saying the Greens are determined the minority Labor Government they support will run a full term.

This forced Prime Minister Julia Gillard to reject suggestions the Greens were determining the election timetable, saying her Government will run three years and "I will decide when the election is on".

In his budget reply speech, Opposition Leader Tony Abbott put his case for an early poll by sharpening his attack on the carbon tax and demanding the Government seek a mandate.

"Only an election could make an honest politician of this Prime Minister," he said last night.

"Only an election can give Australia a government with authority to make the tough decisions needed to build a stronger country and to help Australians get ahead."

But Senator Brown made it clear that if Mr Abbott wants an early election, he will not be supported by the Greens who will control the Senate from July and support the Government with one vote in the House of Representatives.

"Tony Abbott, there will be no election," he told a news conference in Canberra.

"We are not going to put Mr Abbott's overweening personal interest in a power grab under any priority because it leads to instability, self-promotion at the expense of the nation."

Senator Brown says that Mr Abbott did not present a costed budget last night and is "an opposition leader who should stay in opposition".

"The message I give to Tony Abbott is there will be no election. You might wish for it, you won't get it. This country does not deserve to be put through that sort of turmoil just because you want it," he said.

He said Mr Abbott will have to wait "another couple of years - if ever".

Quizzed later on whether the Greens have the power to decide the election timetable, Ms Gillard said: "This Parliament will go full term. I will decide when the election will be and it will be in 2013."

'Like a town drunk'

Nationals Senate Leader Barnaby Joyce says the Government's budget was "like a town drunk with a new pair of socks".

He agreed with Mr Abbott that people want an early election.

"People are just saying, 'I did not vote for a carbon tax and, mate, you cannot cool the planet from a room in Parliament House'."

He says the Government asked the Opposition to release an alternative budget last night.

"This is what they keep asking us. What would you do if you were us?" he said.

"Well, if we were as stupid as you, well, I suppose we would drown ourselves. We don't have to propose an alternative to their stuff-up. We just have to get rid of them."