A woman who had just dropped her children at Otahuhu Primary School in South Auckland drove into three young girls from the same school, leaving them injured.
Police said the girls - two aged five and one 10-years-old - were struck as they crossed Great South Road just before 9am, on their way to school.
Inspector Matthew Child said the older girl was walking ahead of the other children and sustained the most serious injuries. All three were taken to hospital.
Mr Child said the woman driving had just dropped her children at the same school and was heading home.
The 10-year-old and one of the younger girls were sisters, he said.
Witness Janendra Naidu said he heard screams, and saw one child thrown over the bonnet of the vehicle.
Mr Naidu, a manager at New Age Car Limited, said the children were heading to school.
"It was heavy traffic so the kids were trying to cross the road to go to the school nearby and this lady was driving pretty slow, I would say 40 kilometres, maybe, but they just came out of nowhere."
Police commended the efforts of the public who helped wrap blankets around the three children and kept them calm.
The Serious Crash Unit is investigating.