At least 12 people were killed and nine injured on Tuesday evening when gunmen opened fire at an informal settlement in Cleveland, east of Johannesburg, police said on Wednesday.
Police said in a statement that they had launched a manhunt for more than 10 suspects following the attack at the Jumpers informal settlement.
The motive for the attack is not known.
Police said the suspects arrived in a white Toyota Quantum, entered the settlement from two access points and opened fire at multiple locations before fleeing in the same vehicle.
South Africa has one of the world's highest murder rates, averaging about 60 a day.

US to begin enforcing maritime blockade on Iran on Tuesday
Trump says US to reimpose naval blockade on Iran
Ukraine awaits new government after prime minister's shock dismissal
Bangkok pub fire kills 27, police investigating possible negligence
One killed in encounter with US immigration agents in Maine