Businessman Clive Palmer's plan to mine coal near the Great Barrier Reef World Heritage Area has been condemned by Commonwealth-appointed experts who say they see no way to remove the proposal's threat to the reef.

The Independent Expert Scientific Committee (IESC) has expressed "extreme concern" about the proposed Central Queensland Coal (CQC) project, which it said posed "very significant risks" to reef waters and other "internationally recognised assets".

CQC wants to build a mine of up to 10 million tonnes of coal a year — as big as Adani's Carmichael project — 10 kilometres from the World Heritage Area.

But former IESC member Jim McDonald said the expert panel's advice to Queensland and federal environmental officials last month was one of its most damning assessments yet.

"They're quite blunt about the loss of environmental asset," Mr McDonald told the ABC.

"Essentially, they're saying if you go ahead with the mine as proposed, you will lose [some] environmental assets, because there's no way you can offset it."

Mr Palmer is the sole owner of CQC through companies including Fairway Coal and Mineralogy.

CQC has hit back at the IESC, arguing its own draft environmental impact statement "specifically states that there will be no significant impact to any values in these areas", including the World Heritage Area.

Clive Palmer's proposed coal mine site near the Great Barrier Reef World Heritage Area.(ABC News)"Given the findings of no significant impact to these areas, the IESC should state what their 'major concerns' and the 'very significant risks' are," Central Queensland Coal said in a formal reply on Christmas Eve.

But in its third evaluation of the mine proposal since 2017, the IESC said it had previously raised those concerns.

It said it was especially concerned about the "discharge of mine-affected water" into the World Heritage Area and Queensland's largest fish habitat at Broad Sound, north of Rockhampton.

It said the miner's plans to minimise environmental impacts were "likely to be completely inadequate for this region because of its relatively undisturbed setting".

The IESC acknowledged Mr Palmer's companies had done "substantial further investigation and analyses" in response to the panel's previous concerns.

But it said nothing would "alter the material risks associated with this project, in particular the potentially severe consequences for local and downstream water-related assets".

The IESC said the mine risked "significant and irreversible damage to internationally valued estuarine and near-shore ecosystems subjected to mine-affected water".

There was also a potential "legacy water quality issue" from contaminated surface waterways, the "direct loss of 8.35 kilometres of waterways that provide fish passage", and a drop in groundwater of up to 60 metres along an 11.8km stretch of land.