Wildcare Vice President James Fitzgerald said there's an estimated population of around 1000 koalas in the wider region, and that the young male was likely driven out of its range by an older male.

"The boss males drive them out of their mother's home range, and they get lost," he said."We've got contacts with the Australia Zoo, so we've been talking with their vets and we're running all the regulation tests on him to make sure there's not an underlying disease that's cause his poor condition.

"They've said it's very unusual to find one in this condition without an underlying disease," he said.

The young koala is currently being treated at West Queanbeyan Veterinary Hospital and will be released back into the wild by NSW National Parks and Wildlife once it returns to full health.

Mr Fitzgerald urged anyone who finds injured wildlife to contact Wildcare.

"If you find either an injured animal or an animal that's out of place, you should phone Wildcare on 6299 1966," he said.