Monsoonal rain hitting north Queensland has resulted in a release of water from Adani's Abbot Point coal terminal site into the adjacent Caley Valley wetlands.

Key points: Floodwater entered the wetlands from an "authorised release point" at Abbot Point terminal

Floodwater entered the wetlands from an "authorised release point" at Abbot Point terminal Abbot Point Operations said water was not released into the Great Barrier Reef

Abbot Point Operations said water was not released into the Great Barrier Reef Mackay Conservation Group concerned any damage will not be promptly assessed

Operations at the port were suspended earlier this week due to the heavy rainfall that caused extensive flooding in Townsville.

In a statement, Abbot Point Operations — which is owned by the Indian mining giant — said an inspection of the site on Thursday showed floodwater had been released into the Caley Valley wetlands from an authorised release point.

"The inspection indicates there has been no release of waters into the marine environment or the Great Barrier Reef Marine Park, however floodwater has been released to the Caley Valley wetlands from an authorised release point," a company spokesperson said.

"Abbot Point Operations promptly reported these preliminary inspection findings to the Department of Environment and Science.

"Abbot Point Operations will continue to monitor the releases and keep the department informed, and is confident that no environmental harm has or will occur."

Abbot Point Operations said inspection on Thursday revealed water had been released into the wetlands. ( Four Corners: Stephen Long )

Last year, the Queensland Government launched legal action against Adani, alleging one of its companies illegally released coal-laden water near the Great Barrier Reef during Cyclone Debbie in 2017.

Peter McCullum from the Mackay Conservation Group said he was concerned that any possible damage might not be promptly assessed.

"Any water that comes out of a coal port is likely to have significants contaminants in it," he said.

"The Government said back in September last year that they would have monitoring in place at Abbot Point in order to determine whether there was any contamination of those wetlands during the upcoming wet season.

"But as far as we know they don't have anything in place to monitor in real time."

The State Department of Environment and Science (DES) said it had been advised of the water release by Abbot Point coal terminal.

"The stormwater release is currently occurring from a dam spillway as a result of recent heavy rain associated with the monsoon trough," DES said in a statement.

DES officers will be onsite at the coal terminal on Friday morning to assess the situation and ensure compliance with environmental conditions.

A 2017 satellite image of the Caley Valley wetlands (left) after Cyclone Debbie. ( Supplied: Queensland Government )

Previous water release 'exceeded approval'

Adani-owned Abbot Point Bulkcoal was given a temporary emission licence to release some sediment water at its central Queensland coal terminal during Cyclone Debbie.

But the Government claimed the concentration of coal dust in the discharged water exceeded the approved levels by more than 800 per cent.

At the time, Abbot Point Bulkcoal "categorically refuted" any wrongdoing, saying it "fully complied with the conditions imposed by the Temporary Emissions Licence".

In its statement about the latest release, Abbot Point Operations said that since 2017 it had implemented a number of measures to improve environmental management including the commencement of a three-year program to facilitate continuous water infrastructure upgrades.

"These upgrades are improving our ability to mitigate the impacts of extreme weather events such as cyclones and floods," the company said.

"It is important to note that these upgrades as part of this three-year program have already delivered successful outcomes in mitigating a large portion of this weather event by reducing the volume of floodwater released into the Caley Valley wetlands over the past fortnight."