The video shows two suspected robbers who appear to have been cornered in a storage area behind a service station.
The video has been shared on the Heideveld Gang Watch page as well as the Mitchells Plain Gang Watch page.
In it, a group of bystanders, including a number of young children, taunt the suspects while laughing every time they are struck.
Two men appear to be doing the beating – one with a belt and the other with what appears to be a broomstick.
The initial post was shared with the caption: "This happn when you steal.. (sic)"
Some reactions to the post on Facebook include users laughing at the men being beaten.
One user, Fadwa Voterson, said: "...are you people freaking losing it, that is inhuman."
A few users shared her sentiments, while another said simply: "And the poor victims of their crimes? How must they feel?"
A screenshot of some of the comments posted on Facebook
Another, Devorick Geldenhuys, said: "...people are sick of their crap, people working hard to make ends meet, yet they wana take that little joy out of their lives, well I say they got off easily, they should have been stoned, jst to set n example, the entire community should have joined in on the fun (sic)."