"We have always had cadets in schools, and so this was about a reaction to the Defence Force taking rifles into a school," she said.
"We have a lot of kids who are in shooting clubs where they don't actually bring firearms into the school but kids compete. It's not widespread, but it does happen.
"There are also a few rural schools where hunting is the core of the area, and they will often do firearms safety with the police on how to fire a firearm safely."
Kerr serves on the board of Year 1 to 8 Kuratau School near Taupō, which she described as "a predominantly pig-hunting area".
"The school doesn't provide the firearms but it allows kids access to training - not on the school premises, the kids are taken to a firing range, the police are there and firearms safety people are there," she said.
"I believe it's optional and I understand it's senior students".
The draft guidelines say students handling guns in firearms safety courses must be under the "immediate supervision" of a person with a firearms licence.
They allow schools to draw up their own policies for cadet forces, gun clubs and inter-school shooting competitions.