President Jacob Zuma on Tuesday expressed shock and outrage at the deaths of 27 boys who attended initiation schools in Mpumalanga.
"The whole country is outraged at this massive and unnecessary loss of young life at the hands of those who are supposed to nurture and protect them," Zuma said in a statement.
Colonel Leonard Hlathi said on Monday police were investigating 26 murder cases and one inquest. No arrests had been made and police expected the results of the post mortems soon.
Zuma called for swift justice for the victims' families, and for those responsible for the deaths.
The president conveyed his condolences to affected families and said government intended keeping initiates safe in future.
"It cannot be acceptable that every time young men reach this crucial time in their development, their lives are culled in the most painful of ways, in the care of circumcision schools," Zuma said.
Initiation ceremonies are common in South Africa, where youths partake in various activities as a rite of passage into adulthood, usually over the course of three weeks. Some 30,000 youths signed up for initiation this year.
In addition to being circumcised, the boys and young men are put through a series of survival tests which sometimes includes exposure to South Africa's winter with very little clothing. Their faces are painted with red clay and they are given herbal concoctions to drink.
Former president Nelson Mandela described the experience in his autobiography as "a kind of spiritual preparation for the trials of manhood".
Hlathi said on Friday all the deaths occurred at government-registered initiation sites where medical practitioners were usually present.