Teachers fear an increasing number of students will turn up without the necessities to learn as families struggle to afford food, uniforms and stationery.
KidsCan chief executive Julie Chapman told Breakfast this morning that it's "a cost of learning crisis".
She's hearing about it from teachers and principals "more and more".
"More children are turning up to school hungry, and others are missing altogether because their parents aren't able to provide those basics that they need to start the school year and to get on with the business of learning," she said.
Arihia Stirling, the principal of Te Kura Māori o Ngā Tapuwae in South Auckland, said "the struggling was long before Covid" but the pandemic and the recent flooding in Tāmaki Makaurau have added to the issue.
Stirling pointed to the cost of transport and the cost of extracurriculars as other factors putting pressure on families.
"So for instance, for us as a kura, we pay for all activities our children have because we just cannot ask for that extra cost to come from families that are working hard, that are doing two jobs, sometimes three," she said.
"There's lots and lots of things that challenge our communities."
Chapman said: "[At the] beginning of the school year, and actually starting in term four last year, we had 10,000 more children that needed food support across our schools across New Zealand.
"That's continued into 2023 and of course with the floods, particularly in Auckland and Northland and other areas, we know that need is going to continue to rise and there's a much bigger job now that needs to be done."
It can give families "a sense of failure", Stirling added.
"And it's ensuring our children don't feel the emotional struggles that they have about what they shouldn't ask their parents for, that really concerns us," she said, stressing it "absolutely" affects their learning.
"We all know that if you haven't had a decent meal, over a couple of hours that affects the way you think, it affects the way you behave."