Rangitoto College students are rebelling against a "sexist" Year 13 dress code.

More than 800 people signed a petition started on the Change.org website last night stating: "Women are feeling objectified as the rules only being enforced on them, with teachers referencing that they may not wear tights as it gives male teachers arousal."

The petition was taken down today after a deputy principal complained that staff had not used the word "arousal", and the school refutes suggestions its staff have been distracted by female dress.

The college, New Zealand's biggest school with 3157 students, does not require Year 13 students to wear the school uniform but its dress code states: "Smart-casual workplace attire is expected – ie. not dressed for a day at the beach."

Students say the code has been tightened this year to ban low or V-neck tops, tights, ripped jeans, long or coloured fingernails, more than one ring or ear piercing and "anything you can see through, up or down".

"So many people are getting sent home every day and judged, discriminated against what they wear," one student posted on social media.

"I'm not talking crop tops and short shorts because all students understand that rule. But we are talking workout tights and singlets that are apparently arousing our male teachers."

An ex-student said male students were allowed to wear ripped jeans but female students were being sent home for wearing them and for minor issues such as coloured fingernails which used to be allowed.

"The girls feel they are being targeted, especially the girls with a bigger bust. They find they are being discriminated against," the former student said.

"Say you have just got your standard T-shirt on but you're a big-busted girl, they are turning around saying all this sort of thing is provocative towards the male teachers."

A current female student commented on the petition before it was taken down: "So a V-neck top is unacceptable? Sorry I didn't realise that my collarbones are now sexualised."

Another wrote: "It's disgusting that in 2019 Rangitoto College thinks it's appropriate to sexualise young women. If male teachers are aroused by under age female students, they are not fit to work in this environment."

Another said: "Get on with teaching and stop shaming girls for wearing normal clothes."

The rebellion is the third case this year of students complaining about school rules on appearance, after a boy at Auckland Grammar School objected to a rule requiring short hair and a boy at Te Puke High School spoke out against a rule against facial hair.

Rangitoto College principal Patrick Gale said the school refuted the suggestion that male teachers were "distracted" by female students' clothing.

"Rangitoto College has high expectations of all students, including our Year 13 students who wear mufti," he said in a written statement.

"Following an investigation where the dress code was clarified to some of our students, they now understand our position and appreciate the need for dress standards.

"We completely refute the suggestion that teachers are distracted by mufti. While we admire our students' social conscience, we try to ensure that we create an environment for our community that enables all of our high educational expectations to be delivered."