By noon three shark sightings were reported at St James and another at Muizenberg Beach, said spokesman Gregg Oelofse in a statement.
Red flags, indicating high shark activity in the area were hoisted along shark spotting beaches including Muizenberg, Kalk Bay, St James Glencairn and Fish Hoek.
The public were urged to familiarise themselves with the shark warning system and to comply with it.
Earlier in the week 42-year-old British citizen Michael Cohen was attacked by a great white shark at Fish Hoek. A shark flag, indicating the presence of a great white, was flying when Cohen entered the water.
Cohen, who was taken to the Constantiaberg Medi-Clinic, suffered a complete amputation of his right leg above the knee, and a partial amputation of his left leg, below the knee. Source