The Greens' sole lower house MP Adam Bandt's re-election campaign is set for a major boost with the Electrical Trades Union in Victoria to kick in $300,000 for his bid to retain the seat of Melbourne.
The union, which disaffiliated from Labor in 2010, is also considering donating campaign funds to Bob Katter's Australian Party.
ETU state secretary Troy Gray said the union's $500,000 election fund would involve $300,000 for Mr Bandt's campaign.
Before entering politics Mr Bandt worked as an industrial relations lawyer and represented the ETU. Mr Gray said the union's support for Mr Bandt and the Greens was because of his strong record on workplace issues and standing up for workers' rights.
''He is a unique commodity in Australia at the moment, he is an honest politician,'' Mr Gray said.
The ETU is already working under the notion that the Coalition will win office in a landslide. Mr Gray said workers feared a return to WorkChoices-style industrial relations laws in coming years.
''The union's responsibility is to protect workers and the best way possible right now is to support the Greens,'' he said.
Mr Bandt, who is the Greens' deputy leader, has attempted to introduce several laws in Parliament to improve workplace conditions and was a strong advocate for the removal of the Australian Building Construction Commission as well as ensuring its successor did not have coercive powers, which won him ETU applause.
Mr Gray said the $500,000 was open to anyone who was willing to come to the state council and put their case but ''the Labor Party won't be getting a cent''.
Former state secretary Dean Mighell is working with Mr Katter on the new party's IR policy and the union is considering donating to it.
Mr Bandt said he was pleased unions had seen the Greens standing up to protect people's rights at work and the creation of clean energy jobs. ''As we get closer to the election, I hope more workers and unions realise the best way to Abbott-proof their rights is to elect more Greens instead of staying rusted on to a declining Labor Party that takes them for granted,'' he said.
At the 2010 election the Victorian ETU donated $125,000 to Mr Bandt and $200,000 to Greens Senator Richard Di Natale's campaign.