Australian Greens Leader Christine Milne says Labor has walked away from its alliance with her party.
Senator Milne said Labor’s priorities clearly lay with powerful mining interests, not with the Australian people and the Greens.
‘‘What has become manifestly clear is that Labor, by its actions, has walked away from its agreement with the Greens, into the arms of the big miners,’’ she told reporters at the National Press Club on Tuesday.
By choosing the big miners Labor had made it clear it no longer had the "courage or the will" to work with the Greens on a shared agenda for the national interest, she said.
"By choosing the big miners the Labor government is no longer honouring our agreement to work together to promote transparent and accountable government, the public interest or to address climate change.
"Labor has effectively ended its agreement with the Greens."
However, Senator Milne said she would not allow Labor’s failure to honour the "spirit of the agreement" to advance the interests of Opposition Leader Tony Abbott.
"We will not walk away from the undertaking we gave not only to the prime minister but to the people of Australia,"she said.
"And that was to deliver confidence and supply until the parliament rises for the election.
"We will see this parliament through to its full term. The Greens will not add to the instability that Labor creates every day for itself."
Senator Milne told Prime Minister Julia Gillard by phone on Tuesday morning she would be telling the National Press Club the Greens believed Labor had walked away from their agreement.
"I thought I owed her the courtesy to do that," Senator Milne said.
Senator Milne also pitched for voter support for Greens candidates at the federal election on September 14.
"Without the Greens holding the balance of power in the Senate, Australia risks the repeal of the mining tax — giving up on any chance of the Australian community receiving its fair share of the bounty of our mineral wealth," she said.
Mr Abbott has vowed to scrap the mining tax if the coalition wins government.
The senator said this would lead to a "harsher" society with a "conservative agenda that is the exact opposite" of what Australia enjoyed today.
Milne's statement comes on the back of a tough few days for the Government, with speculation surrounding former Prime Minister Kevin's Rudd's alledged leadership ambitions adding to concerns over the Labor Party's poor recent polling results.