Finance Minister Katy Gallagher remains confident the government’s signature climate policy will pass the upper house, despite the Greens hitting out at the plan.

A proposed safeguards mechanism will be the main agenda item as parliament returns for the final sitting before the budget is handed down in May.

If passed, it would apply to the 215 biggest emitters in the country and aim to reduce emissions by 205 million tonnes by 2030.

The government sees the proposal as a top priority and an important part of its climate policy.

But with the coalition opposing it, the government will need the support of the Greens and two other votes in the Senate to pass its election promise to cut carbon emissions.

The Greens have urged the government to stop new coal and gas projects in exchange for their support on the mechanism.

Senator Gallagher said negotiations were continuing with the Greens but she was optimistic of the safeguard’s success.

“We will engage as we do on every piece of legislation because it’s a minority chamber. We have to do that on every single piece of legislation, the safeguards is no different,” she told ABC Radio on Monday.

“We’ve been clear we want this legislation through, it’s critical to meeting our 43 per cent reductions target. It’s the policy that exists now.

“The Greens obviously want some other additional commitments and we’ll work through that over the fortnight.”

Greens leader Adam Bandt said despite flaws in the proposed mechanism, his party was willing to back it in exchange for a commitment to stop opening new coal and gas projects.

A Parliamentary Library research brief on domestic coal demand and supply, commissioned by the Greens, found existing mines in Australia were “adequate” to meet coal-fired electricity demand through to 2040.

“There’s enough coal and gas already in the system for the Australian economy to make the transition to renewables,” Mr Bandt said.

“The new coal and gas projects supported by Labor aren’t about powering our economy – they’re about sending profits offshore tax-free.”

Senator Gallagher said the coalition had dealt itself out of negotiations on the safeguard due to their opposition on the mechanism.

However opposition immigration spokesman Dan Tehan said more information was needed from the government.

“What we want to see is a bit of transparency,” he told Sky News on Monday.

“We want to see the modelling. We want to know what the impact will be on households, what the impact will be on cost of living.”

Meanwhile, more than 50 environmental and climate organisations have joined forces to call on the government to listen to the scientific evidence and stop opening or expanding fossil fuel projects.

Greenpeace, the Australian Marine Conservation Society, Wilderness Society, GetUp, 350 Australia, Lock the Gate, Oxfam and others say there are more than a hundred new coal and gas enterprises under development nation-wide.

“Projects scheduled to begin before 2030 alone will add a further 1.4 billion tonnes (in emissions) annually by 2030,” they said in a statement issued on Monday.

“This excludes emissions from several major projects and vast new gas basins actively supported by Australian governments including the Barossa and Greater Sunrise offshore oil and gas fields, and the Beetaloo, Canning and Lake Eyre unconventional gas basins.”

– AAP