A 56-year-old man is being airlifted following a serious mountain bike crash

A man has been rushed to hospital after crashing his mountain bike near Dwellingup.

St John Ambulance and an RAC rescue helicopter were called to the scene in Nanga Brook — about 110 kilometres East of Perth — just before 11am today.

It is understood the 56-year-old fell off the bike and hit his head.

He was airlifted to Jandakot Airport and then transferred by road to Royal Perth Hospital.

The West Australian was told the man is tonight in a stable condition.