Two customers were shot dead during a business robbery at a Spar supermarket in Germiston on Saturday.

Police said 11 armed robbers entered the store in Van Dyk road at about 16.00.

"The suspects instructed everyone inside the store to lie down and while at it spotted a customer who had a firearm on him. They shot at him as well as a female customer and the two were declared dead on the scene," said Gauteng police spokesperson, Captain  Kay Makhubela.

Netcare911 spokesperson, Shawn Herbst, said paramedics who responded to the scene had on assessment found "that an adult male, (who is an) off duty security guard and an adult female member of the public sustained fatal gunshot wounds" adding that "both patients were tragically declared deceased on the scene".

"The suspects fled the scene with an undisclosed amount of cash. They hijacked two vehicles as they left the store."

Makhubela said one of the hijacked vehicles was later recovered at Vosloorus. He said the suspects were still at large early on Saturday evening.

"A manhunt for the suspects has been launched. Two cases of murder, business robbery and hijacking of motor vehicles were opened," he said.