The community spirit of a small NSW town was key in the moments after a car ploughed into spectators at a demolition derby, injuring 13, the region's mayor said.
Two spectators were flown to Newcastle's John Hunter Hospital in a critical condition after the crash at the Walcha showgrounds, about 90km from Tamworth in the state's New England region, late on Saturday.
The incident at the Walcha Motorcycle Rally occurred when a 27-year-old speedway car driver crashed through a fence and into a mobile grandstand, police said.
Walcha Mayor Eric Noakes said it was amazing how local communities "banded together in these episodes", with a nurse stepping up to triage those injured.
"It's lucky we've got great ambulance and SES and fire (services) in Walcha," he told 2GB radio on Monday.
Federal MP for New England Barnaby Joyce praised "all the off-duty nurses and first responders who immediately dropped everything to help the injured in the storm" at the event.
"Such a sad end to such a great event," Mr Joyce posted on Facebook.
A hospital spokesman told AAP on Sunday that the condition of the two critically injured men had improved to serious but stable.
The 11 other victims, aged 20 to 75, were transported to hospitals in Armidale, Tamworth and Walcha, authorities said.
The driver was taken to Walcha Hospital for mandatory testing, said police, whose investigations into the crash continue.
