The Cairngorms National Park Authority (CNPA), which first approved the proposal to build an eco-friendly village An Camas Mor in 2010, has given planning permission in principle to the development, which will see up to 1500 houses constructed in the park over the next 20 years.
The authority has said it believes the project will ensure sufficient housing in an area where local provision is an issue, but environmental groups have repeatedly objected to the plan.
The Badenoch & Strathspey Conservation Group, the Cairngorms Campaign and the Scottish Campaign for National Parks have lodged an appeal with the UK Supreme Court after losing their earlier legal challenge.
Duncan Bryden, the CNPA's convenor, said: "In the Cairngorms - Britain's largest National Park - many of our much-treasured villages are 19th century planned settlements. An Camas Mòr should be another real living and working settlement for the 21st century that also respects its setting within the National Park. The phasing of the An Camas Mòr project will let the community grow sustainably over time."