The latest body is of a woman believed to be in her 30s and appeared to have bruises and stab wounds, local media reported.
The discovery has sparked fear in the area, particularly among women who say they no longer feel safe.
“We are scared to come out of our houses. We are scared to go to the shops. We are no longer free in a country where we are supposed to be safe as women,” local resident Bongeka Sebela told the BBC.
Police have assembled a multidisciplinary team of detectives, intelligence officers, forensic experts and other specialists to investigate the deaths and establish whether there are links between the cases.
They are also pursuing a person of interest, although they have not disclosed which case or cases that person may be connected to.
“Let’s not get emotional, the gloves are off,” said Gauteng Premier Panyaza Lesufi on Thursday, adding that the authorities had the capacity to deal with the killings.
In a statement on Thursday, South African police said the recent rise in serious and violent crimes against women remained a “matter of grave concern”, urging women in the country to remain vigilant about their personal safety.
They advised women to avoid walking alone or using isolated routes, remain alert to strangers and suspicious vehicles, and share their location or travel plans with someone they trust. They also advised against walking with earphones or earbuds at high volume, warning this could reduce awareness of their surroundings.
“Practising personal safety measures can save lives.”
Authorities have offered a 400,000 rand ($24,000; £18,000) reward for information that could lead to arrests and have appealed to families with missing relatives to help identify the remaining victims.
The discoveries have caused widespread alarm in Ekurhuleni, particularly around Kempton Park, and come against the backdrop of longstanding concern about high levels of violence against women in South Africa.
Police say they are not linking the deaths to a serial killer at this stage, but are investigating the possibility that a group of people is behind the killings.
Acting Police Minister Firoz Cachalia has cautioned against speculation, saying investigators were dealing with what appeared, at this stage, to be “quite distinct, separate events”.
South Africa experiences some of the world’s highest levels of gender-based violence (GBV), with the rate at which women are killed five times higher than the global average, according to UN Women.
Last November, the country classified violence against women a national disaster following an online campaign that culminated in countrywide protests.
