"It was pretty chaotic. She was still on the road, it had obviously only just happened. She was in a pretty bad way," he said.
The off-duty policeman jumped straight into action and began working on the 10-year-old, taking a cell phone off a woman at the scene to describe the crash site and the condition of the girl.
"She was status one, which is basically as bad as you can be. It didn't take me long to figure out how bad it was. I was just trying to control her. A lot of her movement was involuntary, I was trying to keep her still."
He bandaged the worst of the girl's injuries, he said, while the her mother sat beside her constantly talking to her.
"She was distraught, but she did a really good job. The injuries she was looking at; no mother or father wants to see."
It took about 10 minutes for the first emergency services to arrive, he said. Volunteer firefighters from nearby Mercer were first on the scene, followed by a St John ambulance crew.
About 5.45pm, she was airlifted to Starship Hospital, where last night she remained in a critical condition.
Mr Paxton said the response from neighbours at the scene had been a great team effort to try and save the local girl, as well as keeping her mother calm, talking to the driver of the car and managing traffic.
"If you've ever been in those sorts of situations, it feels like forever. It was nice that everyone did their part and hopefully, she pulls through. When people were trying to be calm and help, it all makes a difference."
A Herald Cycle Safe series recently highlighted issues surrounding cycle safety for cyclists and motorists, and generated discussion over issues such as reduced speed limits in residential and shopping areas, cycle lanes, and other changes to make cycling safer.
Cycling advocacy group, Cycling Advocates' Network, has been pushing for a law change to make helmets optional saying there is no evidence that making them compulsory leads to better safety outcomes.
