Slated changes to NSW electoral funding laws have been branded "bizarre" and akin to "match-fixing" by groups from across the political spectrum.
Both unions and the Greens have taken umbrage with different aspects of the government's plan to overhaul electoral funding, to be debated in parliament on Wednesday.
The proposal leaves massive discrepancies in local government spending caps, the Greens say, with political parties banned from spending more than $30,000 in the City of Sydney but in neighbouring Woollahra the limit is $150,000.
While a political party cannot spend more than $30,000 in Campbelltown, it can spend $120,000 in the Northern Tablelands shire of Walcha.
This amounted to about 21 cents per enrolled voter in Sydney but more than $52 per voter in Walcha.
Greens MP David Shoebridge described the laws as "ill thought out and random".
"The government's model is, to say the least, bizarre and the difference across the local government sector produces irrational outcomes," Mr Shoebridge told AAP.
The proposed laws will also prevent third parties acting in concert six months out from an election.
Unions believe the change will kill properly-resourced cross-movement campaigns - including that against WorkChoices and Last Drinks, against alcohol-fuelled violence.
Unions NSW secretary Mark Morey said the government was paranoid and afraid of criticism.
"These laws will prevent civil society banding together and amplifying its voice against the din of conservative governments and deep-pocketed corporates," he said in a statement to AAP.
"This is the political equivalent of match-fixing and anyone with an interest in free speech and robust debate should be concerned."
The proposed laws would also cap electoral spending by third-party campaigners at $500,000. The existing limit is $1.2 million.
The NSW government has been contacted for comment.