Environmental lawyers are examining reports of a threat to the federal Environment Minister from a colleague over the Adani coal mine, which could open avenues for appeal if the project is approved before the federal election.

Key points: Some members of the Liberals and Nationals are worried Adani could be killed off if Labor wins the election

Some members of the Liberals and Nationals are worried Adani could be killed off if Labor wins the election There are pushes for the approval to be made before the Government goes into election caretaker mode

There are pushes for the approval to be made before the Government goes into election caretaker mode Senator McGrath said he would not speak about his reported threat or the approval process

Media reports detail LNP senator James McGrath threatening to call for the Environment Minister Melissa Price to be sacked if she does not sign off on the final Commonwealth approval for the controversial project.

Lawyers "have their antenna up," believing such a personal attack could influence the Minister, Jo-Anne Bragg, the CEO of the Environmental Defenders Office in Queensland, said.

"Such a political threat puts a cloud over Minister Price's possible decisions on Adani," she said.

"That's the sort of cue that would cause us to really dig in and look at the evidence and basis of any decision that she'd make."

The proposed coal mine in central Queensland is a hot political topic, with environmentalists campaigning to have it rejected while local conservative MPs and senators want it approved to bring jobs to the region.

Adani still needs multiple approvals from the Queensland state government, but the final hurdle from the Commonwealth is approval of the company's plan to protect local waterways.

Ms Price is currently considering expert reports from the CSIRO and Geoscience Australia, which have found flaws in Adani's water management plan.

There are already court cases underway challenging other aspects of the approval process, with further legal challenges a real possibility.

"Here we've got a blatant political threat being made," Ms Bragg said.

"It's not the usual case where members of the public or stakeholders or industry point out the benefits or the risks of the project."

Part of the proposed site for the Adani mine in central Queensland. ( Supplied: Lock the Gate Alliance )

Calls to leave approval until after election

The Liberals and Nationals, who want the mine approval sorted quickly, are worried the project will be killed off if Labor wins the imminent federal election.

But some in the Liberal Party would be satisfied if the decision was put off until after the election, fearing backlash from voters opposed to development of a new coal mine.

As well as pressure on Ms Price, Prime Minister Scott Morrison has faced pressure from the mine's supporters to hold off calling an election until the approval has been granted.

The Greens argue the entire process has been compromised.

"It is quite clear that this type of political pressure could make this decision, any decision, that the Minister makes vulnerable to legal challenge," Greens environment spokeswoman Sarah Hanson-Young said.

Senator Hanson-Young wants the Coalition to leave the approval until after the federal election.

"It is just madness for this minister to make any decision on this now. She is clearly not able to make it independently," she said.

Senator McGrath would not discuss the reported threat and was not pressed on the issue in his only media appearance.

"I won't talk about the minister and the process, she's going through that at the moment," he said on Sky News.

"But I am a senator for Queensland, I am not a Canberra senator. Yes, I want it to go ahead because it's about jobs."

Other Nationals have continued to push for the Environment Minister to finalise the approval before the government enters caretaker mode for the election campaign.