Duduzane Zuma was detained briefly on arrival at OR Tambo International Airport on Thursday night.
His lawyer says the son of former president Jacob Zuma was released as there’s no warrant of arrest for an alleged corruption case.
Duduzane is due in court next week on unrelated culpable homicide charges.
In 2014, Phumzile Dube died when Duduzane’s car collided with a minibus taxi in Johannesburg.
Another passenger died in hospital a few weeks later.
Despite a judicial inquest ruling that the deaths were the result of negligent actions, the NPA decided not to prosecute Duduzane at the time.