The US non-profit organisation, Rainforest Alliance, is to develop an online sustainable tourism eco-index of the Americas.

The organisation says that with 700 million people travelling each year, tourism is a growing source of revenue for people living in areas rich in plants and animals threatened with destruction.

"While tourism can lead to problems such as waste, habitat destruction and the displacement of local people and wildlife, it also has the potential to provide incentives for conservation," it says.

The index will help travellers choose destinations that are not only exotic, but also benefit the communities, plants and animals.

The eco-index will offer travellers a searchable database of tour operators, hotels and other tourism facilities that meet certain sustainability criteria.