The group started throwing stones at police who were patrolling the area on foot, said spokesman Daniel Mavimbela.
“A four-year-old boy is receiving medical treatment for an injury he sustained on the upper body. The cause thereof is being investigated.”
Earlier, police said a group of about hundred people attempted to occupy vacant land in the area.
Some members of the group barricaded Ingwenyama Road with tyres and other objects.
A 36-year-old man was arrested in connection with public violence. He is expected to appear in the Randburg Magistrate’s Court soon.
READ MORE: Attempted land grab in Diepsloot