POLICE are concerned for the welfare of a boy who has gone missing while quad biking in the Wheatbelt region of Western Australia.

The 14-year-old boy was on his bike with a group near Brookton, about 140km southeast of Perth, at 9.30am (WST) today when he disappeared.

With temperatures soaring to close to 40C across the state, the boy is believed to not have any water with him.

Fifty State Emergency Service volunteers, along with local police, a fixed wing police plane and a police helicopter are scouring the area to find the youngster.