The Queensland Government has known for more than two years that the site where it proposes to dump millions of tonnes of dredge spoil at Abbot Point was the worst of seven possible options for port expansion from an environmental point of view.

Experts working for North Queensland Bulk Ports, a government-owned corporation which operates the Abbot Point terminal, reported in September 2012 that the site west of the port where the State Government now proposes to dump the spoils offered the lowest cost option for reclamation and expansion and was nearest to the coast.

But the consultants warned: "However, the West Site is considered the least desirable from an environmental and approvals perspective as it will result in the greatest impact on the Caley Valley Wetland and Cultural Heritage values of Abbot Point".

The reports, not previously made public and obtained under Right To Information, show experts considered the risks of expansion on the western site were so high it was in any case highly unlikely it would obtain Commonwealth approval.

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Engineers Aurecon reported in September 2012 under the heading of "Approval Risk": "Approval and potential delay risk high due to loss of wetland area and resulting impacts to wetland species [migratory birds etc]."

And environmental experts E3 Consult warned of "intense scrutiny from community and environmental groups" of such a plan and predicted: "The likelihood of not gaining an approval is very high. Should an approval be granted by the Commonwealth Minister, it is highly likely to be appealed, which could delay the commencement of the project."

Preparatory excavation work could begin in January

Federal Environment Minister Greg Hunt is considering whether to approve a State Government plan to dump about 3 million cubic metres of dredge spoils west of the port as an alternative to a controversial plan to dispose of it at sea on the Great Barrier Reef.

In October, Mr Hunt agreed to a Queensland Government request to assess the project on "preliminary documentation", which streamlines the process.

Premier Campbell Newman's Government reportedly wants to begin preparatory excavation work as early as New Year's Day.

The Caley Valley is a nationally recognised wetland and provides habitat for hundreds of species of birds, some migrating from as far away as the Arctic Circle.

The Newman Government has told the ABC about 150 hectares, or 2.5 per cent of the total area of the wetland, would be affected by the dredge spoil dumping plan.

Environmentalists and the state Opposition have criticised the plan as rushed, warning that not enough is known about how the wetland will react to the development.

Wetland dumping would impact migratory and native birds

The Newman Government is keen to improve coal-handling facilities to kick-start the mining of coal reserves in the Galilee Basin inland of the port, where Indian mining giant Adani has proposed building one of the world's biggest coal mines.

Sorry, this video has expired Jeff Seeney speaks about the Abbot Point plans

"It's kind of an insane idea of really trying to satisfy the pressure from Adani to get this development going as quickly as possible because they've threatened to withdraw from the development if they're not dredging by 2015," Jeremy Tager, of the Far North Queensland Conservation Council, told the ABC.

The office of State Development Minister Jeff Seeney told the ABC that the dumping of dredge spoil on part of the wetlands was expected to result in "impact, both direct and indirect, to migratory birds and the Australian Painted Snipe".

But Mr Seeney said the plan included an offset of 1,400 hectares, many times more than the wetland area affected by the dredge spoil dumping.

"We will offset that with huge enhancement of the existing wetland," Mr Seeney said.

"We're using the dredge spoil as a positive, to enhance an area of port land."

Mr Seeney said avoiding dumping spoil on the Great Barrier Reef was "the best outcome" of the plan.

"Even though the permits were issued for [dumping on the reef], it was an emotive issue that people were not prepared to accept. So we've solved that," he said.

UNESCO has repeatedly threatened to list the Great Barrier Reef as endangered, raising concerns about the potential impact on tourism.

Opposition environment spokeswoman Jackie Trad said she would be surprised if the Commonwealth approved the plan.

"UNESCO is watching," she said.

"The independent experts have said there are other ways to expand the port. If there are other options that are less environmentally impactful, why is the Government taking the quickest option?

"What the Government has chosen is port expansion for one coal company, not a port expansion for the health of the region."