Environmental groups are considering another legal challenge to the Carmichael coal mine in Queensland, which was last week given the green light with "36 of the strictest conditions in Australian history" by Environment Minister Greg Hunt.

Approved in July 2014, the approval was set aside by the Federal Court in August this year after a local environment group highlighted concerns that an endangered lizard and snake had not been properly considered.

But with last week's re-approval, the Australian Conservation Foundation (ACF) said the strict conditions included in the approval were in fact weaker than those originally imposed.

"In the previous approval, if Adani wanted to make any changes to the plans to protect the environment, they needed to seek the minister's approval to do so," ACF chief executive Kelly O'Shanassy said.

"Under this second approval process from Greg Hunt, Adani has the power to create changes in their plans without seeking any approval from the minister."

In a statement, a spokesperson for Mr Hunt said the change simply cut red tape that did not result in an environmental benefit.

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"Suggestions that the conditions for the re-approved Carmichael coal mine project are weaker than the earlier approval are just plain wrong," the spokesperson said.

But Ms O'Shanassy said the new condition was "like putting the fox in charge of the hen house".

She said Adani had a poor track record of environmental management internationally.

"For example in India they removed 75 hectares of mangrove conservation zone and they built an airport without permission," she said.

"Why our Government would allow this company to actually change plans to protect the environment without any approval power is beyond me."

Some conditions imposed on Adani: Implement advice from Independent Expert Scientific Committee on Coal Seam Gas and Large Coal Mining Development

Implement advice from Independent Expert Scientific Committee on Coal Seam Gas and Large Coal Mining Development Protect and improve 31,000 hectares of southern black-throated finch habitat

Protect and improve 31,000 hectares of southern black-throated finch habitat $1 million research funding to improve conservation of threatened species over 10 years

$1 million research funding to improve conservation of threatened species over 10 years Protect Doongmabulla Springs through monitoring of groundwater and triggers to enforce limits

Larissa Waters, deputy leader of the Greens, said she would be seeking clarification on how the new condition slipped into the approval.

"I will be asking in Senate estimates of the environment department, is this the first time that you're letting a company effectively rewrite their management plans without the minister needing a tick-off, and is this your interpretation of a strict condition?"

"I don't trust the companies to self-regulate. That's what we have an environment department and an environment minister for.

"I think it's outrageous for Minister Hunt to say this is a strict condition when actually it looks like he's taking a very hands-off approach."

Adani has been told to improve 31,000 hectares of habitat for the endangered black-throated finch. ( Supplied: Coast and Country )

The mine, proposed for the Galilee Basin, 300 kilometres inland of Bowen on the Queensland coast, would be Australia's largest coal mine.

The company said it would potentially provide 10,000 jobs to the region, but Greenpeace calculates it would also release 128 million tonnes of climate-changing carbon dioxide into the atmosphere each year.

Ms O'Shanassy said environment organisations would consider further legal action against the mine but she denied it was simply a delaying tactic.

"Environment groups don't want to delay this coal mine, ACF doesn't want to delay this coal mine — we want to stop it. It's really dangerous," she said.

"It produces or will produce more pollution per year than New Zealand or the state of Victoria, and in a time of global warming it's really dangerous to be building new coal mines."