Former Greens leader Bob Brown has welcomed his party's decision to effectively end its formal alliance with Labor.

Mr Brown negotiated the power-sharing agreement with Labor after the 2010 election, but yesterday Greens leader Christine Milne declared that deal over.

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In a speech to the National Press Club, Senator Milne accused Labor of becoming too cosy with the mining industry and putting their interests ahead of the public.

Mr Brown told AM this morning that Senator Milne has made the right decision.

"They need to look at the disruptive lot that they have become," he said.

"It's very much the Greens clearing the air, because the trouble that Labor's finding itself in would not have occurred if it had kept to the spirit of the agreement, as written out in the preamble.

"It's as simple as that."

He says Opposition Leader Tony Abbott is on track to win the balance of power in both houses of Parliament and that the Greens are trying to stop that happening.

"The Greens are the backstop for the Australian people, not only in the Senate, but with Adam Bandt in the seat of Melbourne," he said.

Today, Prime Minister Julia Gillard said she was not surprised the Greens had effectively ended their deal with the Government.

"The Greens party is fundamentally a party that would prefer to complain about things than get solutions," she said.

"Second, I'm not surprised that the Greens party has walked away on the basis of a difference about jobs - we will always stand up for the jobs of Australian workers."

'Good riddance'

The manoeuvring by the Greens is taking place as Labor deals with poor poll results and worsening internal divisions.

Tasmanian Labor MP Dick Adams says it is a win-win, because the Greens will still ensure the budget passes in May, but other links will go.

"Good riddance to them, as far as I'm concerned," he said.

"There's been some stifling of debate and discussion because I believe people have been worried about what the Greens think of this and that.

"I don't think that's treated Labor very well at all."

Mr Adams says the Greens' latest public statements are motivated by politics.

"They whinge and moan about party politics all the time but they're a political party and they do everything like all other political parties," he said.

"They've sent Bob Brown off to negotiate with the Liberal Party on preferences for the seat of Melbourne.

"They're in there negotiating, and grubby politics, like everybody else."

Preference deals

The Government is demanding the Greens reveal whether they are negotiating a preference deal with the Liberals in Melbourne.

But Mr Brown says to his knowledge, that is not happening.

"There's been no negotiations with the Liberals or for that matter the Labor Party in Melbourne," he said.

Another Labor MP told AM that the shredding of the alliance is more about the Greens abandoning a sinking ship.

Senator Milne's announcement was symbolic but is unlikely to create any day-to-day disruption for the Government, as the Greens have guaranteed supply and confidence for the rest of the parliamentary term.

Independent MP Andrew Wilkie has labelled the end of the alliance as a charade motivated by the pending election.

Mr Wilkie, who withdrew his support for the Gillard Government over a year ago, says he is not surprised that the Greens and Labor want to put distance between each other ahead of the September poll.

"I don't think much has changed, except for how it looks," he said.

"There was an element of charade in it.

"I think if the Greens were fair dinkum yesterday, what they should have said was this is so important to them, that they're fair dinkum and that they also withdraw certainty of supply and confidence, and they didn't."