A wheel-chair bound man has been found dead in his bedroom after a suspicious house fire in South Australia's Riverland.

Crews arrived at the Barmera house just before 7.30am to find it fully ablaze, and took 40 minutes to extinguish the fire.

They then made the grim discovery of the wheelchair-bound man's body in a bedroom.

Another person inside the home managed to escape and was treated for smoke inhalation.