Former Nationals leader Barnaby Joyce and Morrison cabinet colleague Keith Pitt have called for the Coalition to abandon the Paris global climate change agreement and related emissions reduction targets, as the prime minister accused opposition leader Peter Dutton of walking away from climate action.

Dutton has said he would oppose the government’s target of a 43% cut to 2005-level emissions by 2030, telling the Australian newspaper there was “no sense in signing up to targets you don’t have any prospect of achieving”.

In 2022, he said he would adopt a 2030 target that was more ambitious than the 26-28% reduction promised when Scott Morrison was prime minister.

Pitt told Guardian Australia that the Coalition should consider quitting the Paris agreement which commits signatories to set periodic targets to limit global heating, arguing the transition to renewable energy was costing Australians too much.

“If that’s necessary in order for people to have a roof over their heads and pay their bills, then that ought to be considered,” Pitt said on Monday.

Joyce said that “in the end, aspirations have to take a secondary position to the economic reality”.

“You cannot destroy the economy for the purposes of a policy,” he said. “The political reality that sits behind that is if the lights go out and the economy is shelled out, you’ll get voted out.”

Anthony Albanese seized on the policy shift, accusing Dutton of ditching the Coalition’s commitment to address climate change.

“His decision to abandon the 2030 target means him walking away from the Paris accord,” Albanese said on Monday. “You can’t shape the future if you’re afraid of it and Peter Dutton is afraid of the future and he’s incapable of leading Australia towards the future that we need.

“Peter Dutton is worse than Scott Morrison on climate change. He is all negativity and no plan.”

The Paris agreement is a legally binding commitment to hold global heating at below 2 degrees celsius – and ideally 1.5 degrees – compared to pre-industrial levels. With only Libya, Yemen and Iran declining to join, its signatory countries have subsequently agreed to a target of achieving net zero emissions globally by 2050, with interim emissions reduction targets for 2030 and 3035.

The government insists Australia is on track to achieve a 42% reduction – still short of its 43% target – and measures recently announced in the budget will provide further help. But some analysts have said it will likely fall short and the Coalition argues that makes the target pointless.

The shadow energy minister, Ted O’Brien, insisted that the Coalition remained committed to the Paris agreement – even though it requires countries to progressively increase their commitments and not backslide once a target has been set. Dutton’s remarks appear at odds with that.

“The Coalition is absolutely committed to the Paris agreement and we’re also committed to net zero,” O’Brien told ABC Radio National. “There’s no doubt targets are important but they have to be well informed and they have to be achievable… Of course we will be signing up, in government, to targets, not just net zero.”

On Sky News, O’Brien said the Coalition would commission modelling before setting its target.

“We will be as ambitious as we can,” O’Brien told Sky News. “But we will be contained by what’s achievable – and we’ll be honest and transparent.”

Nationals leader David Littleproud appeared to differ, suggesting on Monday that the Coalition “won’t have a linear pathway” to net zero and that nuclear power would deliver a sharp reduction in emissions when it was up and running, meaning the Coalition would not need to transition to renewables, or away from fossil fuels, so soon.

“There will be a ramp up at the end in us achieving that goal of net zero by 2050,” Littleproud told Sky News. Later, he told constituents: “We don’t need to do it all by 2030.”

Speaking to Guardian Australia, Pitt went further, insisting the priority commitment should be “to the Australian nation, not the United Nations”.

“People are hurting and anything we have to do to help them, we should do,” he said. “So if that means a disagreement with the United Nations on previous agreements in order to help the Australians in their time of need, then that’s what we should do.”

Joyce said his deal with Morrison to endorse a net-zero 2050 target never included any agreement on a target for 2030.

“In my discussions with Scott Morrison, I was quite explicit that we didn’t agree to a 2030 target,” Joyce said, arguing it was irrelevant whether the Liberals had accepted that position or not.

“If you say ‘I’m not going to marry you’, it doesn’t matter whether they accept it or not.”

Former prime minister Malcolm Turnbull said withdrawing from the Paris agreement would “definitely be a negative” for investment in Australian renewable energy.

“The curious thing from an electoral point of view is why Dutton is doing it because nuclear power is not going to deliver cheaper electricity - that’s perfectly clear - and it’s not going to deliver electricity any time soon,” Turnbull told ABC TV.

“It will take decades to establish nuclear power plants and we don’t have an abundance of time. And so it seems to me and to many other people in the Liberal party that it’s an approach that’s going to further alienate the very people whose votes were lost in 2022.

“And they don’t see - I don’t see - how it’s going to assist Peter Dutton in winning government. It will probably just ensure he doesn’t win any teal seats back and perhaps loses more.”

Independent senator David Pocock condemned the Coalition for considering watering down the targets.

“That would be an extraordinary act of vandalism against the people and places we love and we should be pushing both sides of politics and particularly the government to ramp up their ambition,” Pocock told ABC television.