An investigation has begun into how 10 lightly clothed schoolgirls got lost in the Kaimai range bush for eight hours in plummeting temperatures.
The review comes as a bush safety expert says anyone heading into the bush should at the least carry spare clothing and food supplies in a backpack.
A group of 50 Tauranga Intermediate pupils were taken on a bush walk on Tuesday afternoon as part of school camp to Ngamuwahine Lodge but 10 girls, aged 11 and 12, went missing.
Search and rescue volunteers, Tauranga's Trustpower TECT Rescue Helicopter and the Auckland-based police Eagle helicopter scoured the bush.
Despite plummeting temperatures and a lack of warm clothing, the girls were found safe and well 10km from the lodge nearly eight hours later.
Tauranga Intermediate principal Brian Diver told the Bay of Plenty Times teachers and pupils involved would be interviewed.
Four adults were supervising the group on the walk, which was expected to take about an hour.
Mr Diver said it was still unclear where three staff members and a parent were when the girls became separated.
"That's the very question we will be asking: How is it that 10 girls go missing?"
Answers were also expected as to why the pupils only had light clothing with them.
"There will absolutely be a review in to the circumstances and what will happen with that review will go in front of our Ngamuwahine trustees and from that we will work out how we can prevent something like what happened last night from happening again," Mr Diver said.
Despite initial anguish, Mr Diver said he had only received positive feedback from parents since the group was found.
"Of course we all felt anxious, we felt upset, we felt nervous. That's how people felt, but I reassured them that we have got excellent systems in place and had total confidence that those girls would be found," he said.
Mr Diver said the girls had returned to the camp yesterday and were "hale and hearty".
Western Bay of Plenty area commander Inspector Clifford Paxton has been reported as saying there was concern the girls were lightly dressed on such a cold night.
Temperatures went as low as 4C earlier in the evening.
Chris Owens, programme manager for bushcraft and risk management for New Zealand Mountain Safety Council, said anyone heading into the bush should at least carry spare clothing and food supplies in a backpack.
"Hypothermia can be an issue if you are not dressed appropriately and the outdoors becomes quite cold at this time of year. We always recommend that you take safety supplies," Mr Owens said.
The risk of hypothermia varied with each person.
"If you are very fit and fairly large it takes longer but if you are smaller and and not as strong it is much less," he said.
Mr Owens said although the school's initial walk was not a trekking day-trip "the fact it turned into several hours changed the dynamic somewhat".
There were many factors that could affect trampers in the bush such as rising rivers or becoming lost. It was important to be prepared for this reason, Mr Owen said.
"Plan your trip, tell someone, be aware of the weather, know your limits and take sufficient supplies. We believe that these apply to anybody going into the great outdoors," he said.
General guidelines for school field trips and outdoor activity did not specify ratio numbers for supervision.
The guidelines state: "EOTC [Education Outside The Classroom] activities involving large groups can be more effectively managed when the large group is divided into smaller groups, each with its own leader.
"An effective supervision plan for a large group should allow for the person in charge to be free from directly supervising students ... so that [person] can have an overview of the whole group."
A spokesman for the Ministry of Eduction said any legal issues or deviation from the guidelines lay with the school's Board of Trustees.