Six people have been killed in an accident involving a truck and a taxi on the N3 south on the Heidelberg off-ramp in Ekurhuleni.
Ten others have been injured.
Officials say the freeway heading south will be closed for the next four hours beginning at Gray Avenue.
Emergency services Vincent Khoza said: “The freeway entry direction south will be closed at Gray Avenue and the Heidelberg off-ramp for the next three to four hours.”
This is the latest in a series of major accidents over the past few weeks.