The Forestry Commission has offered talks with the White Horse Association to spell out the risks so volunteers can decide if they want to train for certification at their own expense.
But Association chairman John Bielby said: “We are not confident that (the commission) has any intention of letting us back on the Horse and we believe it just wants us to raise funds so, for this reason, we fear we may have come to the end of the road.
“It will be a sad end to a dedicated band of volunteers.”
Thirsk and Malton MP Kevin Hollinrake said: “I cannot see any reason why the maintenance activities should not continue until there is firm and unequivocal evidence on health and safety or other grounds for them to cease.”
Forest management director at the commission Alan Eves said: “As the owner of the site, the Forestry Commission has legal responsibility for all activities undertaken and we can’t allow unauthorised activities to take place, irrespective of the past safety record of the volunteers or the insurance cover they may have.” He added that the situation will “ remain under review”.