Some secondary schools are asking parents for more donations this year, despite the economic downturn.
Principals say they have little choice because the money they get from the Government no longer covers basic costs.
A Weekend Herald survey of 62 schools in the upper half of the North Island found a wide range of policies towards donations, which are officially voluntary.
Auckland Grammar School charges parents $860 a student and $1720 a family per year - the highest school donation fee out of any of the schools surveyed.
Headmaster John Morris said the concept of free education was a misnomer. "Government funding will never be enough to run schools and hence school donations are one way of being able to maintain an excellent standard of education that people expect from Auckland Grammar School."
The school cannot legally force families to pay the fee but Mr Morris said that as a decile-10 school, and having the lowest Government funding, it encourages parents to pay by giving them options of paying monthly.
Auretta Perrin, principal of Bay of Islands College, said her school stopped charging a donation because hardly any parents ever paid it. "Chasing it up almost cost the same as putting the money in ourselves," Mrs Perrin said.
Instead, the decile-one school asks parents to pay for any extras their children may require - technology equipment, school trips, cultural and sporting activities - and finds parents are willing to donate their time to help the school, if they are not able to donate funds.
Decile-six Te Awamutu College raised its school donation fee 100 per cent this year.
Principal Tony Membery said the school had kept the fee at $50 a student for the previous eight years but it was time to be "realistic" as it was charging less than similar neighbouring schools. About half the school's parents usually paid the donation.
Auckland Girls Grammar also raised its school donation - from $180 for one student to $220 - for the first time in 11 years.
Westlake Boys High, a decile-nine North Shore school, raised its donation fee 35 per cent to $475 for a student and $650 per family.
Principal Craig Monaghan said the operations grant was not meeting what most schools needed to cover. Most parents pay the donation and the school is flexible with payments. "I think to expect every parent to pay when they've just forked out for uniforms and stationery is unfair."
He said Westlake Boys relied heavily on funds from parents and its 120 overseas students, who pay fees similar to those charged by New Zealand private schools.
Edgewater College principal Allan Vester said it was the schools in the middle decile range which were in a difficult position when parents did not pay.
His decile-four school received $201 a student in state funding and around 40 per cent of parents donated $125 a year, while a high-decile school nearby got around $40 in Government funding and received an additional $460 a student from 85 per cent of families.
Mr Vester recognises there are two sets of parents who do not pay their school donation: those who cannot afford it and those who choose not to because they see almost no consequences of not paying.
For the past decade, Henderson High School , which is decile four, has helped around 50 parents each year to buy uniforms. Principal Joy Eaton hopes 30 to 40 per cent of parents will pay donations, which are kept reasonably low.
The money goes towards sports equipment and upgrading classroom equipment but is always seen as a "bonus" so the school would not rely on it for the core expenses.
Ms Eaton said the school operated a hardship fund out of the sale of second-hand uniforms and other fundraising efforts.