Police say they are "extremely" concerned for the welfare of missing Wangara man John Williams.
A massive search is underway near the 79-year-old's Gnangara Road home, with a particular focus on the Kingsway sporting complex.
The State Emergency Service, police mounted division, police airwing and 4WD vehicles are involved in the search.
Mr Williams, who has a medical condition, has not been seen since 11am on Tuesday.
His abandoned car was found at Kingsway Shopping Centre yesterday after security staff noticed the vehicle had not been moved since Saturday. There was a stench of rotting food emanating from the car.
CCTV shows Mr Williams doing his shopping at the centre on Saturday. He returned to his car sometime later and collected his black kelpie.
The man and dog were last seen near his home on Tuesday.
Acting Inspector Chris Ruck said because of Mr Williams' age and medical condition, and last night's close-to-freezing temperatures, police were extremely concerned for his welfare.
Mr Williams is described as being fair-skinned, about 181cm tall with a slim build and short dark hair.
He was last seen wearing black tracksuit pants, a maroon jacket, a grey cap and black shoes.
Anyone who has information on his whereabouts is asked to contact Police on 131 444.