High school children are among seven people injured in a crash between a school bus and a van on State Highway 1.
The crash happened just before 8.20am between a Leabourn Passenger Service bus and a black Honda Odyssey about 20m into SH12 from the SH1 intersection on the southern side of the Brynderwyn Hills.
St John treated seven patients at the scene, including five who were taken via road ambulance to Whāngārei Hospital in a moderate condition. The other two were in a minor condition and did not need hospitalisation.
It is understood 18 people left the scene before emergency services arrived and were taken to Otamatea High School, in Maungaturoto.
A St John spokeswoman said a Primary Response in Medical Emergencies doctor - a rural doctor called to major incidents - and an ambulance were also going to the school as a precaution to check on their condition.
A statement from the school said it and health services were supporting students involved.
"The school remains open for instruction as normal - and we will continue to offer support to all the students and families at this time."
A reporter at the scene said the van in the crash had been towed away while the bus is parked on the roadside and police serious crash investigators are talking to the driver.
Traffic is free flowing, no roads are blocked. Road maintenance crews are cleaning up the road.
Three ambulances, a helicopter and a manager were called to the scene, St John said.
A witness on the street said a woman and four children - including a baby - had been in the Honda Odyssey that had just turned into SH12 and then stopped to turn into a nearby carpark.
The witness said the car had been stationery, indicating to turn right as a truck was coming in the opposite direction on SH12. The bus came from behind the family's car on SH12 and hit the back of it, pushing it into the path of the oncoming truck.
"I just looked outside the window and just saw the car being squashed.
"The bus came around the corner... the bus slammed into her."
The witness said she immediately went down to help.
"I ran down and made my kids bring blankets and water.
"Another lady had arrived too and was helping the kids out of the car. Those kids... they were not good," she said, taking a deep breath.
"They stuck to her like mama bear."
The witness said she and a number of other members of the public managed to get the woman and the children safely out of the vehicle before emergency services arrived.
The children and woman, who she guessed was their mother, appeared to be in shock after the crash.
The witness said locals often dropped off their children at the bus stop on SH12.
Many parents would drive into the carpark the woman was trying to go into, before children crossed the road to wait for their school bus.
"It's very dangerous. I've been saying that for years," the witness said.
"Even though my kids are teenagers now - and are embarrassed - I still cross the road with them because it's just so dangerous ad I just want them to get there safely."
Asked how she was feeling now, after this morning's events, she said she herself was still in shock.
"It was just horrendous," she said.
"I'm still jittery - I'm having a coffee and thinking about whether I should go to work or not."
The police Commercial Vehicle Investigation Unit is looking into the crash.
Kaipara District Mayor Jason Smith told Radio New Zealand the bus had picked up students from the Kaiwaka and Mangawhai districts.
"We're just extremely concerned for these patients and the students of OHS [Otamatea High School] and the drivers of the other vehicles as well, that everyone is well and safe and gets home at the end of the day. That's the most important thing," he said.
"We don't have a fatality and that is a blessing in this situation."
He said the community was aware of how vulnerable school buses were on open roads, and since the Highway Cafe closed at the junction it had been an empty stretch of motorway.
"The Brynderwyn intersection is a very challenging piece of road because traffic is coming off SH1 often at high speed onto SH12 so you have a confluence of roads and a carpark and pulling over bay."
Earlier, about 8.05am, a car crashed into a barrier outside Countdown Supermarket at the Okara Shopping Centre. The crash saw a window in the shop shattered. It was believed to have been caused by a medical event.
Meanwhile, a flat deck truck carrying a house has collided with power lines in the Hikutaia area in the Coromandel.
A police spokeswoman said police were called to the incident on State Highway 26 near Corbett Rd about 7.08am.
The highway is closed between Paeroa and Kopu and diversions are in place at State Highway 2, Hauraki Rd and State Highway 25A.
- additional reporting, RNZ