South African leg-spinner Imran Tahir was allegedly subjected to racial abuse during the fourth one-day international against India at the Wanderers Stadium last Saturday.
In a brief statement, Cricket South Africa said it was aware of video footage of Tahir being circulated on social media.
According to the statement: "Imran Tahir was verbally and racially abused by an unknown man. Tahir reported the incident to the stadium security and was subsequently accompanied by two security personnel to identify and to have the man ejected from the stadium.
"Tahir made no physical contact with the offender or any of the children in the vicinity. The incident is under investigation with the CSA and stadium security teams."
The Cricbuzz website quoted South African team manager Mohammed Moosajee as saying that Tahir, who was not in the playing 11, was abused by the same person whenever he went onto the field on drinks duties. Tahir believed the spectator was an Indian supporter.
Moosajee said there had been some "hostile verbal exchanges".
A Cricket South Africa spokesman said later on Monday that the organisation was waiting for a full report from security officials.