An environmental group says the Buller District mayor is being disingenuous by claiming coal mined from the Denniston Plateau will be cleaner than that from other countries.
The Environment Court has issued resource consent for a Bathurst Resources to open a coal mine on the plateau, north of Westport.
The company hopes to be producing coal by early next year.
Mayor Garry Howard says the high quality coal extracted will be environmentally friendlier than that from China or India.
However, Coal Action Aotearoa spokesperson Kristin Gillies says that argument is misleading.
He says all coal contributes to global warming and the planet cannot afford for any new coal mines to be opened.
"There's no such thing as environmentally responsible coal. 80% of the world's coal needs to be left in the ground and what that means is no new coal mines, and that any existing coal mines should be left to run their course."
Mr Gillies says Westpac Bank should also withdraw its support for the Denniston Plateau mine.