The Greens have increased pressure on the two major parties on Senate voting reform by bringing forward a private member’s bill that would make it harder for micro parties to win a seat.

The private member’s bill advocates optional preferential voting below the line and abolishing above-the-line group ticket voting, and was endorsed by the Greens at the party’s national council meeting this weekend.

The endorsement showed Senate voting reform was a “key priority for the Greens”, federal senator for New South Wales Lee Rhiannon said, adding that the party had been pushing for reform since 1999.

Both changes listed in the private member’s bill were initially recommended by a joint parliamentary committee report looking at Senate reform, released in May 2014.

The changes would effectively lock out minor party senators such as Ricky Muir of the Motoring Enthusiasts party, who entered the Senate on just 0.5% of the Victorian vote after complex preference deals.

Unsurprisingly, many of the crossbench senators are against reforming the system.

The leader of the Palmer United party, Clive Palmer, denounced the move on Twitter on Monday.

Govt proposed voting reforms to eliminate preferential voting attempts to rig Senate results and destroy democracy in Australia #auspol — Clive Palmer (@CliveFPalmer) June 29, 2015

Govts proposed voting reform is designed to limit choices. Politicians only care about themselves and not the country #auspol — Clive Palmer (@CliveFPalmer) June 29, 2015

The Coalition has started informal consultations. A spokeswoman for leader of the Senate, Eric Abetz, told Guardian Australia that “the government is considering the [2014] report”.

It has not yet put forward legislation, one of the reasons the Greens have taken matters into their own hands.

“I think the momentum is there for [change],” Rhiannon said.

A deal with the Greens would give the Coalition the numbers in the Senate to pass reforms, although no model has been introduced.

It would also mean the Coalition would not need to rely on support from Labor, which is deeply divided on the issue.

The shadow special minister of state, Gary Gray, “strongly supports” the report’s recommendation, a spokeswoman has told Guardian Australia.

But right faction powerbroker Sam Dastyari has warned that accepting the voting changes would be “madness” because it would reduce the impact of the progressive vote in the Senate.

Last month Penny Wong appeared cautious on the changes when questioned on ABC radio.

“As Senate leader my … obligation I think is to look at what the potential impact of any voting measures would be on Labor and on the Senate more broadly,” she said.

Senate reform is flagged as one of the issues the Coalition wants to resolve before going to the next election. Enacting a double dissolution would mean the threshold for a Senate seat would be halved, as all seats would be vacated giving micro parties more of a chance.

