The Scottish Secretary, Donald Dewar, last week approved public funding for a funicular railway in the Scottish resort.

The World Wide Fund for Nature and the Royal Society for the Protection of Birds are arguing for a judicial review to try to stop the scheme.

Outside the court, WWF spokesman Simon Pepper said: "A funicular railway will quadruple or quintuple the number of visitors coming to the area and that is not just going up the hill but going to the car park at the bottom.

"Now that inevitably raise risks of further damage and concern on our part."

The case centres on protection for nearby conservation areas protected by British and European laws.

The funicular has a modern, continental design

The £15m Alpine-style funicular is intended to rejuvenate the reputation of the Cairngorms as a ski resort.

Announcing its intention to fund the railway, the Chief Executive of Highlands and Islands Enterprise, Iain Robertson, said: "This project is of national significance for Scotland's tourism industry and also for the development's pioneering combination of visitor facility and environmental gain."

But the umbrella group set up to oppose the railway questions HIE's claim that the project will bring 200,000 visitors a year to the area.

Bill Wright of the Save the Cairngorms Campaign asked: "Where is the new business going to come from?

"The ski lift company is hoping to attract more people to the Cairngorms but all they will be doing is moving existing business from other ski centres such as Anoch Mor and Glenshee. It just means that other areas will suffer."

The railway would be the first of its kind in Britain, replacing the aged chairlift currently used to get skiers up the ski slopes on the 4,084ft mountain.

Scottish National Heritage decided to stop opposing the railway in March after changes to the proposal.

Hamish Swan of the Cairngorm Chairlift Company appealed for other groups to join them.

"It's very disappointing because we've gone down the road all the way to meet the environmentalists, we've given them just every single point that's been raised and it would be nice to see them coming towards us.

"I'm still very hopeful that the environmentalist, particularly the RSPB and the WWF, will come on board and help us develop our facility because they know a great deal about the area and I'd like to see a bit of partnership."

However, the campaigners say even if they lose this case they will go on to try to block £3m in European aid being sought for the railway.