Twenty-eight female guards were unfairly dismissed by a security company because the client‚ Metrora.
A union representing cash guards is infuriated at the alleged use of "hit squads" by the guards' employers to interrogate and assault their members.
The Motor and Trade Worker's Union (MTWU) said the police must put an end to the "reign of terror by the hit squads".
Solly Mthibedi, a MTWU national coordinator, said his union was calling for the arrest of hit squad members and "everyone linked to them".
"We have received numerous complaints from our members. It is time the police stepped in and ended this terror," he said.
Gauteng police spokesman Director Phuti Setati said yesterday the police would only take action after charges were laid.
"I encourage victims to report the matter to the police. What they are doing is illegal and should be stopped," said Setati.
Coin Security has refused to comment.
Sowetan revealed earlier this week that cash-in-transit guards were allegedly victimised by what they called a "hit squad".
The guards said the hit squads were hired by Coin Security several years ago to "extract" confessions from guards after money has been lost during heists.
They alleged that whenever management suspected an inside job, the hit squads would interrogate them.
The guards said to extract confessions hit squads would assault them with batons and shock their genitals with electric prongs or suffocate them with bags.