The two organisations will act as advisors and set environmental targets for the project, which combines the construction of holiday homes with a nature conservation and reforestation programme in an area south of Lisbon.
It is the first in a series of proposed 'One Planet Living' developments across the world that follow principles developed by WWF and Bioregional.
The aim is for each resident to live within an ecologically sustainable unit, defined as 1.9 hectares per person, without sacrificing quality of life.
Bioregional has already advised on the development of an eco-village in Beddington, Surrey, which consists of 100 homes and work areas.
That design will be used to formulate the building plan of the larger Portuguese project.
"It's about finding a way to reduce our ecological footprint," said Bioregional director Pooran Desai. "These are communities of the future that accept that we have to take a fair share of the earth's resources."
The Portuguese project is being built and funded by real estate firm Pelicano. WWF and Bioregional will carry out an ecological audit of the project after it is complete. Bioregional is committed to 100 days consultancy a year for the duration of the project.
The area will use renewable energy resources such as solar power and will not use any carbon-based fuels. There are also 20-year targets for reducing the carbon dioxide emitted in travelling to and from the area by 50 per cent and for eliminating waste.
Most of the 4,300 hectare site will comprise forestry and protected conservation areas. But tourist and residential facilities will cater for 30,000 people, and include a 'green' golf course fed only by treated waste water and maintained without pesticides.
Building is due to start in the first half of 2005. Future 'One Planet Living' developments are planned in France, China and South Africa. A 2,000-home development is also proposed for East London.