The two women at the centre of a dispute that ended with one pinned against a tree by a car were friends and colleagues who had been staying together, a friend says.
Police have charged a 50-year-old Beach Haven woman with wounding with intent to cause grievous bodily harm after she allegedly ran down her 55-year-old friend, injuring her leg.
She will appear in the North Shore District Court on Monday.
The older woman remained in hospital last night following surgery to repair her foot.
A relative of the victim said he could not understand what went wrong between the pair.
"The one who was hurt was staying with [the accused] and helping her out," he said.
The two women were friends and worked together as cleaners, he said.
The incident occurred in Salisbury Rd, in Birkdale.
The incident began just after 4pm when a car the women were in came to an abrupt halt in the middle of a roundabout.
Witnesses said one woman jumped from the vehicle and began chasing the other, at one stage throwing a rock at her. Punches were thrown, and one woman was screaming at the other, "you shouldn't have done it", they said.
People nearby had tried to calm the situation, they said.
A 17-year-old resident who ran to the scene after seeing the drama unfold said the injured woman was in a great deal of pain.
A man who was leaving a nearby dairy said he heard a "heated argument" with quite a bit of swearing.
Another person arrived at the scene to find the injured woman propped herself up against a fence, he said.
"The first thing I did was call out to one of the customers at the dairy and told them to call the police."
A St John Ambulance spokeswoman said the injured woman was taken to Auckland Hospital with moderate injuries.