Environmentalists will launch court action against the federal government and its decision to allow dredging and spoil dumping in Great Barrier Reef waters for the expansion of coal export terminals at Abbot Point.

The Mackay Conservation Group, given $150,000 raised by activist group GetUp!, will file documents in the Federal Court on Monday challenging the decision on the grounds that the government failed its legal obligations to protect a world heritage site by approving the project.

The Great Barrier Reef.

It is the second legal challenge to the proposed Abbot Point development. Last month the North Queensland Conservation Group launched an appeal against a separate decision to allow the dumping of dredge spoil in reef waters by the authority which oversees the marine park.