Reports of racial segregation at a private school in Pretoria are a shocking indication of the persistence of racism in post-apartheid South Africa, the Ahmed Kathrada Foundation said on Friday.

"Schools are meant to be laboratories of nation building, not enclaves of outdated apartheid thinking," the foundation's director Neeshan Balton said in a statement.

"The justification of needing to enable learners to maintain their cultures is exactly the kind of arguments put forth to justify apartheid, and has no scientific or educational basis," he said.

Balton congratulated the parents for refusing to accept the "separate but equal" arguments put forth by the school management.

Eye Witness News reported on Thursday that Curro Roodeplaat Private School had been accused of assigning pupils to classes based on their race.

According to the report, almost 30 parents at the school reportedly signed a petition demanding an explanation from the school.

Regional manager at Curro Holdings, André Pollard, denied that the school was racially segregating its pupils.

"It is not because we would like to segregate the whites, it is just because of friends. Children are able to make friends with children of their culture," he told the broadcaster.

Later on Thursday, CEO and founder of Curro Holdings Dr Chris van der Merwe said pupils were integrated across various grades.

"This is done in a manner that fosters a secure learning environment in which all learners can flourish. This principle applies equally across all Curro schools," he said.

Van der Merwe said that Curro collectively had about 36,000 pupils in their 42 schools, and that 63 percent of these pupils were black.

"Our philosophy has always been and will continue to be to create accessible education to South Africans from all backgrounds."

The school had reportedly scheduled a meeting with parents on the matter on Thursday night.

According to EWN, parents wanted to know why some classes were made up of only black children, while the white pupils were kept together.

Pollard told the broadcaster that the number of white pupils at the school was very small, therefore the school was trying to keep them together.

Once there were 12 or more white children, they would separate them equally into the classes, he told the broadcaster.

The department of education on Thursday expressed concern over the issue and said it would send officials to the school on Friday to ascertain "what happened, how it happened, who was involved and what appropriate steps should be taken," said Phumla Sekhonyane at the time.