Environmental activists on Monday launched an unprecedented court challenge on climate change grounds to Anglo-Swiss miner Xstrata's plans for a mammoth Australian coal mine.

Brought by landowners and green group Friends of the Earth, the case is seeking a ban from the Queensland Land Court on the Aus$6 billion (US$6.2 billion) Wandoan open-cut mine, which plans to export 30 million tonnes of thermal coal a year.

Believed to be the first ever Australian court challenge to a mining project on climate grounds, it argues that the emissions from mining and burning the coal would have a significant impact on the local and global climate.

Friends of the Earth claim the project will significantly and irreversibly damage icons of the country's northeastern tourist region including the Great Barrier Reef and tropical rainforest through worsening global warming.

"This mega mine will be one of the largest coal mines in the world, and contribute a sizable 0.15 percent of annual global emissions every year," said spokesman Bradley Smith.

"This might sound like a small number but in fact it's the equivalent to the combined emissions of 72 countries around the world and roughly equivalent to the fossil fuel emissions of New Zealand."

Xstrata is the world's largest exporter of thermal coal and the sprawling 32,000-hectare (80,000-acre) Wandoan project -- a joint venture with Japan's Itochu Corp and Sumitomo Corportation -- is expected to have a 30-year life.

The company has received conditional environmental approval from the government and insisted it had "followed a rigorous environmental assessment and review process throughout each stage of the Mining Lease Application process".

"Objections have been received on issues including: the impacts of mining, greenhouse gas emissions associated with the mining and subsequent burning of the coal, road access to landholder properties, effects on cattle, and groundwater impacts," the miner said in a statement about the case.

Xstrata's lawyers plan to call expert environmental witnesses and will also argue that there will be massive economic benefits to the local community.

Landowners claim the mine will destroy some of the region's best grazing and cropping land and will affect air, soil and water quality, local wildlife and and the health of livestock.

Xstrata has conceded that available agricultural land will be reduced by 40 percent in the region during the mine's life, but says all holdings would be fully rehabilitated once the lease has expired.