Treasurer Jim Chalmers urged MPs to choose to help Australians who are being confronted with “unsustainable, unacceptable” energy price rises, by supporting the proposal.

“Without intervention, next financial year retail gas prices are expected to increase by a further 20 per cent and electricity prices by a further 36 per cent,” he told parliament.

“That’s why urgent action is needed.”

Chalmers said the government respected the role the gas industry played in Australia’s economy but had a responsibility to find a solution to protect Australians from increasing power bills.

The new laws propose to cap gas at $12 a gigajoule, introduce a mandatory code of conduct for the gas market and roll out power bill support for welfare recipients.

Labor has a majority in the lower house, and the Greens and independent senator David Pocock have confirmed they would side with the government in the Senate.

Greens leader Adam Bandt sought an amendment to freeze power bills for the next two years by increasing taxes on gas and coal companies.

Independent MP Andrew Wilkie also supported a windfall tax on energy companies who were “shamelessly profiteering” off the war in Ukraine and soaring prices, at the expense of Australian consumers.

Opposition Leader Peter Dutton said the coalition backed relief measures but wouldn’t back the bill as it did not want market intervention.

But Prime Minister Anthony Albanese said the former coalition government had been “addicted to power and hopeless on energy”.

“Now they’re seeking to stand in the way of this urgent action because they imagine that somehow it serves their political agenda,” he said.

“Vote for this plan and be part of the solution or vote against it and be part of the problem.”

Dutton said the government appeared to be “building the plane on the runway” when it came to energy relief and had presented a plan at the last minute.

“The government is more interested in the political advantage than trying to help families … we don’t support market intervention that is going to disrupt investment into our country,” he said before the sitting.

“The fact is power prices will continue to go up and up and up under this government because they’ve got no idea what they’re doing.”

But Australian Energy Regulator chair Clare Savage said energy contracts for next financial year were already heading in the right direction, easing fears prices were set to skyrocket.

She said government modelling showing prices would be $230 less than expected was likely around the mark.

“Since the government started talking about intervention in fuel markets in the October budget, the cost of one of those contracts has already fallen about 45 to 50 per cent in NSW and Queensland,” she said.

“If these markets keep trading as they are right now, we should see an increase next year that’s much lower than what we’d originally feared.”

The treasurer urged all MPs to be on the “right side” of solving the nation’s energy woes.

“That’s what this choice, this coming vote, really comes down to: higher power prices or lower power prices, relief on energy bills or no relief, protecting Australian industry and jobs or leaving (them) swinging in the breeze,” he said.

“This bill is in the national interest for all Australians.”

-AAP