The Porsche 918 Spyder, driven by a British businessman, appeared to spin out of control as he was driving at high speed along an airport runway used for the event.
Paul Bailey has been named as the driver of the car and is still in hospital along with others. Five of the injured, including a six-year-old girl, are said to be in critical condition,
Eyewitness video filmed by a spectator shows the car losing control before spinning, crashing through a barrier and into a crowd.
The injured are seen on the ground with one person apparently wedged between two damaged vehicles.
Maltese Parliamentary Secretary, Chris Fearne, said some of the injured suffered severe head injuries, multiple fractures and abdominal injuries among others and psychologists were helping the victims, the Times of Malta reported.
An eyewitness also told the Times of Malta one of the car's back wheels touched the grass which caused it to spin.