UPDATE: A BOY who was reported missing at the weekend has been found alive in Western Australia's Wheatbelt region.

Dennis Dear, 14, who has autism and cerebral palsy, was riding his quad bike with his father in Flint, about 80km southeast of Perth, at 9.30am (WST) yesterday when he disappeared.

Police had been concerned Dennis would be exposed to the 40C heat and it was believed he didn't have any water with him.

His quad bike was found last night and he was found this morning.

Police say a helicopter is taking Dennis to hospital for a check-up and they described him as being relatively well.

State Emergency Service volunteers, police, officers from the mounted section and the police helicopter were involved in the search.