Labor's preference deal with the Australian Greens continues to draw scathing criticism from the opposition with one senior Liberal labelling it a "grubby backroom" agreement.
Labor's national executive on Saturday confirmed the Greens would be preferenced second on Senate tickets across the country, except for Queensland, where the Katter Party will be favoured.
National secretary George Wright said the decision offered Labor the "best chance of winning majority government".
But the coalition has slammed Labor for its willingness to trade votes.
"Labor would rather link up with a party that doesn't support a modern economy, that opposes forestry, that opposes sugar, opposes mining, opposes manufacturing," opposition spokesman Christopher Pyne told Network Ten.
The coalition was putting the Greens last because they were "bad" for Australia and Labor should have done the same.
"Instead they're continuing their dirty deals, their grubby backroom arrangements designed to keep the Greens and Labor in power and chaos and dysfunction ruling Australian politics."
Opposition Leader Tony Abbott on Saturday criticised the preference deal which is likely to bolster the Greens' chances of retaining seats in the Senate that would otherwise have been at risk.
Greens Deputy Leader Adam Bandt said his party's alliance with Labor stems from the need to prevent a Coalition dominance in parliament.
"The arrangement that has been reached is done with the aim of stopping Tony Abbott having total control of this parliament," Mr Bandt told reporters in Melbourne on Sunday.
"Tony Abbott's real agenda is one that should send a shiver down the spine of many Australians".
Mr Bandt said a Coalition government would take backward steps on climate change, while cutting funding to health, education and welfare.
The Greens' sole representative in the lower house, Mr Bandt said the party intends to win and retain his seat of Melbourne "in our own right".
He said Australians should vote first for the Greens and then allocate preferences of their choosing.
"There's an agreement between Labor and the Greens that will see Labor preferences coming to the Greens in the Senate and in many places around the country, especially in those marginal seats, there will be Greens recommending a preference to Labor in House of Representative seats," Mr Bandt told reporters in Melbourne.
A statement from the Greens later said Labor should be preferenced along with "progressive minor parties" ahead of the Coalition.