Associate Professor Tonia Gray, from the school of education at the University of Western Sydney, said that for ''screen-agers tethered to their computers or TV screens'', school-based outdoor education programs might offer their only opportunities for outdoor exploration.

''School-age children today are using social media, computer games and television for their entertainment,'' she said. ''What this will create is a generation of outdoor-illiterate adults.

''Outdoor educators are already noticing that Australian children cannot walk confidently and skilfully in outdoor environs. They are unfamiliar with uneven ground, crossing rivers or negotiating steep hilly terrain. They've got absolutely no motor co-ordination or skills to deal with it.''

Outdoor education was needed now more than ever, said Scott Polley, a University of South Australia lecturer and representative of Outdoor Education Australia.

''We've had a major shift from general outdoor play to indoor activities and this has potential psychological and physical health consequences,'' he said.

''Once we would have assumed that all kids would get dirty and play in the creek and enjoy just being outside in the fresh air. In parts of society, we're now seeing a lot of kids who struggle to walk on a track or see a bug and are quite scared of it. The outdoors is becoming a scarier place for kids … we're building up these ideas we have to protect ourselves from the outdoors, instead of immersing ourselves.''

Antony Butcher is a co-director of Land's Edge, which provides outdoor education programs in Sydney, the Illawarra, Kosciuszko National Park and on the south coast for students from years 2 to 12.

''Generally, the opportunity for kids to experience the outdoor environment - and certainly off the sporting field - is diminishing,'' he said.

Outdoor education allowed children to explore personal identity, community and the environment, helping them build resilience and encouraging communication, teamwork and problem-solving skills, he said.

Activities such as rafting, camping and bushwalking were ''a big contrast to the structured learning environment of the four walls of the classroom. The key thing is the … interaction with others and the environment that the activities foster''.

The draft ''shape paper'' for the national health and physical education curriculum proposes that outdoor education continue as an elective in years 11 and 12.

With the final shape paper for that curriculum released this month, Associate Professor Gray wants the Australian Curriculum, Assessment and Reporting Authority to stipulate that students should engage with nature.

But Associate Professor Andrew Brookes, of the school of outdoor and environmental education at La Trobe University, said the curriculum ''has quite reasonable provisions for outdoor education and environmental awareness. Schools run outdoor programs in quite different and diverse ways at the moment and as far as I can see there's still plenty of room for that in the national curriculum.''