The ACT National Parks Association president has never forgotten it.

"I was pretty awe-inspired because I realised they had come down from Charlotte Pass, across the unbridged Snowy River and then negotiated several kilometres of gravel track with a normal wheelchair," Mr Griffiths said. "That stuck in my mind. Then last year I saw in a magazine that the Victorian parks system had two all-terrain wheelchairs in use.''

Mr Griffiths approached his association about donating a TrailRider, or all-terrain chair, for use in the ACT's reserves.

The organisation handed over the wheelchair at an open day at Tidbinbilla Nature Reserve on Sunday.

The one-wheeled chair supports the rider's weight, while handles at the back allow two, three or four sherpas to guide the chair along the tracks.

Mr Griffiths said the chair, which will be based at Tidbinbilla, would allow mobility-impaired visitors to make better use of Canberra's reserves.

"It's much more manoeuvrable than a standard wheelchair," he said.

"It allows them to go further into the bush than they would normally be able to," he said.

"It's such an important thing getting people into the bush. It contributes to the community's understanding of nature and reminds us why we have these fantastic reserves.

Lyneham resident Peter Clarke volunteered to give the chair a test run. "The fact that this is being offered as a service is magnificent," he said.

"I'm glad it's got brakes, because going downhill in this thing is hard sometimes."