By Tess Ikonomou in Canberra

Mega political donations would be slashed under a crossbench proposal to “clean up politics”.

Independents and the Greens have teamed up to get a suite of changes over the line in time for the next federal election, which must take place by 2025.

The Fair and Transparent Elections Bill will be introduced in both chambers of parliament in a united front by Senators David Pocock, Larissa Waters and Curtin MP Kate Chaney.

Under the reforms, a donor cap would prevent an individual from donating more than two per cent of the public funding paid for the last election, which was $1.5 million.

It also contains a truth in political advertising provision, a ban on donations from socially harmful industries including fossil fuels, and to lower the donation disclosure threshold to $1000.

But it excludes a cap on spending on elections, which was a recommendation from the electoral matters committee.

Senator Waters said the group was taking action after waiting for 18 months for the Albanese government to implement its election pledge to “clean up politics”.

“This bill has the numbers to pass if the government gets on board,” she said.

The Greens senator said the joint-forces feared Labor was “stitching up a deal” with the coalition that would shore up the two major parties.

Asked about the lack of a spending cap, Ms Chaney said the proposed donor cap was simple and would unlikely be challenged in the High Court as it allowed competition.

“The compromise that we’ve come to is a donation cap that still prevents an individual from having a disproportionate impact, but allows multiple people to make donations and for campaigns to actually spend the money that they’ve raised,” she said.

“I don’t think there’s a problem if you get a large number of people donating a small amount of money each …  that feels like it’s actually democracy working.”

Clive Palmer, whose company Mineralogy donated $7,088,867 to the United Australia Party in 2022/23, has said a spending and donation cap could be challenged in the High Court.

Warringah MP Zali Steggall described the team up as a “people power coalition to bring about change and integrity to our electoral reform”.

The crossbenchers say if the government adopts the legislation, it could pass without the need for negotiations with the coalition.