Cash-strapped parents have had to apply for more than $6.3 million in advance benefits to pay for their children's school uniforms, stationery and fees in the past year.
In addition, nearly $275,000 has been distributed in special needs grants to cover the same costs in emergencies.
The figures, which show a dramatic increase in people needing help with school-related costs in the past 10 years, are expected to get worse when GST goes up in October.
Budget advisers say parents are already stretched to their limits and will struggle even further when general living costs increase to the point where many families will have nothing left for things such as education.
Figures released by the Ministry of Social Development to the Herald show nearly 40,000 people applied for an advance on their benefit in the 2009-10 year in order to pay for school-related costs.
Of those, more than half needed help paying for $5.1 million worth of uniforms - an amount which has nearly doubled in the past 10 years.
Nearly $1 million was paid out for school stationery, while $251,000 was given to parents needing helping covering school administration costs and examination fees.
An advanced payment of benefit is available to all Work and Income clients who need help paying for an essential items. The money is non-taxable and interest-free and can be applied for more than once, but must be paid back. There is also a special needs grant which both beneficiaries and non-beneficiaries can apply for in an emergency that does not have to be repaid.
The figures show the number of people applying for that emergency help has nearly trebled in the past 10 years, while the amount of money given out has increased fourfold.
In the 2009-10 year, $225,000 was paid out for uniforms to nearly 1000 applicants. Ten years ago, that amount was just $53,000 and given to just over 300 applicants.
Beneficiaries Advocacy and Information Services manager Pam Apera said she wasn't surprised the number of people applying for help with school costs had increased.
"There's nothing left in the budget for them to put money aside for those things and particularly with schools requiring uniforms.
"The rate children grow, you might have to replace uniforms twice in one year, and so if you get an advance from Work and Income for one lot of uniforms and books, you are still paying that off by the time you need to get another advance."
Darryl Evans, chief executive of Budgeting and Family Support in Mangere, said there had been cases where children simply weren't going to school because their embarrassed parents couldn't afford the cost of things such as a school shirt or a pair of shoes.
Mr Evans said he was dreading the GST increase, which would only make things worse for families.
Social Development Minister Paula Bennett said: "We are committed to providing help to those in genuine need."
GST increase the last straw
It's hard enough meeting the general costs of living these days, let alone paying for the school-related expenses that come from having a teenage daughter.
Auckland mother Pauline, one of the 40,000 people who applied to Work and Income for help with educational expenses in the past year, says the cost of sending 15-year-old Annie to high school has increased to the point where she doesn't know how she will manage once GST increases from October 1.
"I have had a lot of help covering her costs. I can't afford it through my normal benefit.
"I've had to get advance after advance to be able to get her things she needs like her school uniform and textbooks.
"When they get into senior years, they need a heck of a lot of extra things."
Pauline, who has a disability that stops her working, says it is an "embarrassment" having to tell her daughter she can't afford the same things her "rich friends" get, but it's a struggle just to cover the basics.
"I say, 'I'm sorry, I just don't have the money'."