They were treated at the scene by St John Ambulance.
Kerikeri Fire Brigade had checked the gas cylinders on the delivery truck and found no leaks.
The investigation was continuing.
Iwashita urged drivers to take care when overtaking on rural residential roads.
''There's trucks, fruitpickers and residents coming and going all the time,'' he said.
It is understood the 28 children at Nurture by Nature were taken to the end of the property furthest form the road.
The speed limit on Kapiro Rd is 100km/h.
Some residents have campaigned long and hard for reduced speeds.
The limit on Waipapa Rd, which also runs off State Highway 10 north of Kerikeri and has a similar mix of residential, horticultural and industrial properties, is 80km/h.
After a spate of serious crashes in 2017 one Kapiro Rd resident went as far as replacing the speed limit signs with 80km/h signs she had made herself. They were promptly removed.
The Far North District Council has previously said 100km/h is appropriate for Kapiro Rd, but speed limits in the Kerikeri area are due to be reviewed again later this year.
