One person was killed and 18 others were injured when the aircraft hit a factory near the Wonderboom airport.
While the aircraft that crashed was painted in Martin's Air Charter livery, it wasn't owned or operated by Martinair, the unit of Air France-KLM said in a statement posted via Twitter.
Russel Meiring, a spokesman for paramedic company ER24, says the injuries in Tuesday's crash range from minor to critical.
He said: "We suspect that the plane was on its way to the Wonderboom airport".
Police spokesman Isaac Mahamba told South African broadcaster eCNA: "There is smoke all over and paramedics are on the scene".
Tshwane emergency services' Johan Pieterse says four of the injured passengers were trapped in the wreck and they had to use specialised rescue equipment to free them.
Unconfirmed reports said one person was critically injured.
The plane, which had been expected to arrive at the Aviodrome on Jul 23, "crashed in South Africa during take-off on a test flight", it said.
It was unclear how many people were on board the plane when it went down.
The 50-seater plane crashed shortly after takeoff.
Civil Aviation Authority (CAA) spokesperson Kabelo Ledwaba said their investigators were on their way to the crash.