Balmoral School principal Malcom Milner said a parent who arrived back from Australia had pointed out the hazard and on finding out their uniform hat did not include that safety feature, called on parents to remove the cords.
"We thought...you know, kids run round and things like that - so we're just being cautious around having hats and we're currently talking to our supplier about altering the design of our hats.
Dear Parents/Whaanau,
The school has become increasingly concerned about the safety hazard that the hat cord on school...
Posted by Friends of Balmoral School on Wednesday, 22 February 2017
"Any new hats that we procure will take that into account - that the cord gets ripped, there's a cord on that can easily spring apart or I know some hats have a elastic just around the head. That's what we will do.
"I know some of the hats that when they're pulled on, they rip off. They break. But the current model that we have don't, so it's just a precaution."
There has been no blanket ban on hats with cords on this side of the Tasman.
The Ministry of Education said whether or not a school had a uniform - or what was included in that uniform - was not something enforced by them, but something schools were responsible for.
Head of sector enablement and support, Katrina Casey, said: "It's not something we have a particular view on, although we do think it's important that schools communicate very clearly with parents what their requirements are.
"That then allows parents to make informed choices when deciding which school to send their children to.''
Casey said the board of trustees for each school decided what students wore and where a uniform was introduced, as well as the design.
"Parents should ask about the expectations and likely cost of school uniforms before they enrol their children."
Milner said they had never had an accident where a student had been injured because of the cord on their hat.
But taking preventative action was the best answer for them.
"If you know this now and anything happened to a child at your school, you'd be devastated as a parent and as a teacher.
"As schools, we're obliged to look at our health and safety and well-being of our children and our staff.
"So I suppose it's saying: 'Hey, if there's a potential for an injury here and we can minimise that potential, then we will [take] action.''