A bomb scare led to the evacuation of all passengers and staff at the Lanseria Airport, west of Johannesburg, on Saturday.
An eyewitness said flights going in and out of the airport had been delayed after a suspicious bag was found abandoned.
Planes expected to land at the airport had been given alternative landing areas.
Dudu Qubu, who was at the airport, said a bomb squad had arrived.
"As we were waiting, we were told that there is a bomb scare as someone has left a bag attended since 1pm."
Later, Gauteng police Captain Katlego Mogale said that the bag had contained a "white substance" which was sent for testing.
Mogale added that cigarettes, dried dates and clothing were also found in the bag.