Two women believed to have spiked their alleged victims' drinks before robbing them, have been arrested.

The two, aged 25 and 31, were arrested in Mamelodi and are suspected of stealing a Mazda 3 and cellphones of victims who were reportedly found unconscious in a Mamelodi cemetery three months ago.

"The victims, who had met the suspects in Sunnyside before they passed out, were transported to a local hospital for treatment," police spokesperson Captain Daniel Mavimbela said.

Now Sunnyside police have relaunched an investigation into cases where victims were reportedly had their drinks spiked and their property such as motor vehicles, cash, cellphones and household contents allegedly stolen following interaction with new-found friends, Mavimbela said.

He said police also recovered the victim's cellphones in Mamelodi and seized tablets and a substance that are believed to be responsible for inducing deep sleep in victims.

The suspects are expected to be charged with possession of illegal drugs and theft and will appear in the Pretoria Magistrate Court soon.