AN onlooker has been left fighting for his life after a flash fire from a car on the track at a Red CentreNATS event spread through a fence and hit the audience.
Another 12 people, have been transported to Alice Springs Hospital in a serious but stable condition.
One man was in a critical condition.
The incident occurred at about 3.45pm.
In one version of chilling footage of the incident, a man can be heard saying "I can't believe I just got that on video, holy sh-t." The man than realises the seriousness of the incident and says "Oh my God there are people who have been burnt."
St John Ambulance southern commander Andrew Everingham said they responded to reports of a flash fire from a competitor's car which resulted in burns to members of the audience.
"St Johns has treated and transported 12 patients with varying degrees of burns and injuries," he said.
"One was in a critical condition - 11 in a serious but stable condition with various degrees of burn injuries."
One eyewitness who was about 100m away from the incident said everyone in attendance was concerned for the people involved.
"Everyone applauded when the organisers announced the event would be ceased for safety," they said.
"Their main concern was for the people involved."
NT Major Events said the welfare of the injured was their key concern.
"This is a distressing situation, however all patients are receiving the care they need," the spokesperson said.
"Due to the incident, the organisers ceased the competition so the focus can be on the people who are in need of assistance.
The incident is currently being investigated by police.
If you have concerns for friends and family please contact the Alice Springs Hospital on (08) 8951 7777.