The most expensive uniform was Mt Albert Grammar with a full girls' uniform costing $703.50.
It was closely followed by Burnside High School where a full girls' uniform sets parents back $694.90.
And girls' uniforms were often more expensive, even at a co-ed school.
At Mt Albert, a full girl's junior uniform costs $703.50 with three blouses, six sets of socks, a skirt and trousers while a full boy's uniform is $599.50.
Girls' trousers cost $71.50 while a boy's pair costs $60.
And a skirt costs $85 while boys' shorts cost $60.
At Avondale College in Auckland, girls' junior shorts cost $59 while boys' shorts $50.
And at Burnside High School, which has a gender-neutral policy so students can wear either uniform option, skirts are $75 while shorts are $35.
Principals at the schools could not be reached for comment yesterday.
A parent of a girl about to start Year 9 at Rosehill College in Auckland said the price of getting her a uniform was "absolutely disgusting".
The father is a single parent who works fulltime but said he was still recovering from the expensive festive season.
"I was unable to take her away for a holiday because I knew I was in for $1000. By the time I bought uniforms, a Chromebook, stationery, school bag and shoes I spent $950.
"It's just criminal and I only have only child. I feel for families who have more children."
Another single parent also contacted the Herald about the cost and said she paid hundreds to send her two children back to school.
Another mother said her child's uniform was "a bloody stretch on the budget", with it costing just under $700.
"Their father refused to help with the cost which means a big strain on me financially to get them back to school for the year. Generic uniforms would be fantastic."
This idea was floated by several people who contacted the Herald, with one parent suggested New Zealand adopts a system like the one in the United Kingdom.
There you can buy generic uniforms at budget chain stores and parents just need to buy the right school colours.
"The schools have a monopoly and they all have different uniforms, so there are no economies of scale in the market."
A survey by Postie found 44 per cent of parents had to make sacrifices in order to afford their children's uniforms but that number jumped to 64 per cent for those who earned $50,000 or less.
And 78 per cent of parents who earned less than $50,000 said they felt unsure, worried or confused about the money they needed to save for school uniforms.
The Ministry of Education yesterday announced it was investigating the price of school uniforms but said it would not be subsidising the prices at this stage.
THE COST FOR A SCHOOL UNIFORM
The cost of a girls' uniform at Mt Albert Grammar School
Jersey - $98
Three blouses - $168
Skirt - $85
Trousers - $71.50
Jacket - $97
PE shorts - $33
PE shirt - $43
Pantyhose - $10
Wide-brimmed hat - $20
Scarf - $38
Two sets of socks (three pack) - $20
TOTAL: $703.50