Anthony Albanese says Labor should not single out existing projects, like the Adani coalmine, that have already gone through approval processes “and then retrospectively change existing laws, which would have ramifications across the board”.

The Labor frontbencher has effectively ruled out Labor overhauling the Environmental Protection Biodiversity and Conversation Act as part of a strategy to boost legal options of killing the controversial Queensland coal project.

While Labor has been considering a range of policy options, including the possible insertion of a climate trigger in the Act, Albanese told the ABC “certainly there has been no suggestion from Labor that that is something that we should do”.

“We haven’t said at any stage that we would do that.”

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He added that the Adani project had already secured the required environmental approvals “not once, but twice. It was approved firstly and then they made a decision that what they would need to do is to re-examine it in light of the potential impacts on the Great Barrier Reef and again it was approved”.

“It has received its state approvals – both of those rounds of approvals by the way under Coalition governments, not Labor governments.”

And referencing the byelection in the Melbourne electorate of Batman, where the Greens are already escalating their ground campaign efforts against Labor on Adani – Albanese explicitly warned colleagues against making a short-term political decision that would have long-term policy implications.

“What you can’t do is look at any one electorate and say this is why we are going to determine national policy on something like mining or energy or climate change action,” Albanese said.

“What you have to do is to get the policy mechanisms right and that is what we have done.”

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The Labor leader, Bill Shorten, has been publicly telegraphing a hardening of Labor’s position on the Adani project since late January, but has yet to clarify what specific options the ALP might take.

This week, Shorten has been visiting Queensland coastal electorates, and sending a positive message about the future of coal, while also highlighting his concerns about the Adani project.

Labor’s climate change spokesman, Mark Butler, delivered a much less equivocal message. On Monday he used his speech to the Sydney Institute to argue developing the Galilee Basin was not in Australia’s national interest because it would displace mining and jobs in existing coal regions, and would not help the world meet its obligations under the Paris climate agreement.

Internal views within Labor are mixed, with some key players favouring killing the project on climate grounds, but others concerned that option will expose Labor to a damaging political backlash about sovereign risk.

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The mining union has urged Labor not to toughen its position on the project, because stopping Adani will trigger an internal debate inside the party about the future of coalmining, and will cost the ALP politically in Queensland.

Albanese said he did not believe the Adani project would ultimately proceed, because it would not get government subsidies, which would help the mine attract private finance.

“The conservation movement said to me repeatedly ... this project doesn’t stack up unless it gets some public subsidy through the rail line,” Albanese said.

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“Now we ensured that that would not occur and indeed the Queensland Labor government has also said that they won’t support that subsidy and hence we have a project that doesn’t have any finance here in Australia, unable to raise funds in the US, unable to raise funds in China – and therefore it is hard to see this project going ahead because of the economics of the project”.

Adani has confirmed it has now abandoned its March deadline for securing financing for the first stage of the Carmichael mine.