The Queensland Government has uncovered a large coal spill at a mining port near the Great Barrier Reef.

Investigators found spillage from a ship loader at the Port of Hay Point, and at Louisa Creek Beach near Hay Point's two export terminals.

Their search was triggered by complaints from locals, who said coal and fine black dust were washing up at East Point beach near Mackay.

Hay Point houses two separate export terminals, and is the largest such facility in proximity to the Great Barrier Reef.

“That investigation has found one larger and one smaller source of coal spillage,” said Queensland Environment minister Dr Steven Miles said.

“But it's not possible yet to say if [Hay Point] is the source of the coal that has washed up on those beaches.

“The footage I've seen suggests it's in a pretty solid state and is washing up onto the beach.

“I will seek advice about how this coal could be impacting on local marine life.”

Reports say departmental officers saw at least one significant spillage of coal from a ship loader during their inspections of Hay Point.

Smaller spillages were alleged spotted from trestles transporting coal to ship loaders at both terminals.

A laboratory will soon receive samples to test and confirm the origin of the coal.

“There are multiple terminals, multiple ships running through those terminals,” Dr Miles said.

“So we do need to see this investigation proceed. I am seeking and receiving regular briefings.

“So nobody should doubt that this is being taken very seriously, and when the source is identified then the environment department will take appropriate action.”

The Australian Maritime Safety Authority is now involved in the investigation too.