The Mackay Conservation Group will launch proceedings today in the Federal Court in a second legal challenge involving the Abbot Point port expansion.

The group is disputing federal Environment Minister Greg Hunt's decision to allow dredging inside the Great Barrier Reef Marine Park.

It is also appealing the Great Barrier Reef Marine Park Authority's decision to allow the dredge spoil to be dumped on a sand bed within the park's boundaries.

Speaking on the case, MCG coordinator Ellen Roberts said Hunt had failed in his duty to protect the World Heritage-listed reef, as required under the Environment Protection and Biodiversity Act.

"A successful case could have implications for the protection of other Australian World Heritage sites," she said in a statement.

"This case has implications for all of the development of state-owned ports and trans-shipping proposals along the Great Barrier Reef and the World Heritage Committee's looming decision over whether to list the reef as 'in danger'."

Activist group GetUp is funding the legal case, which is being argued in court by the Environmental Defenders Office of Queensland.

GetUp is also funding another case against the marine park dumping, which will challenge the science behind GBRMPA's decision.

The EDO is arguing the same case on behalf of the North Queensland Conservation Council.

GetUp has raised $300,000 to fund both cases.

The North Queensland Bulk Ports Corporation is set to deliver the Abbot Point port, near Bowen, south of Townsville.

The development will turn the port into one of the world's biggest coal terminals.

The dredged material is expected to be deposited in an area 25km from the port and 20km from the nearest coral reef.