The head girl at Ravenswood on Sydney's Upper North Shore has used Speech Day to accuse those running the school of putting its image ahead of the welfare of the students.

A former private school chaplain has backed up her depiction of Ravenswood, and said elite schools more generally are obsessed with "money, image and advertising".

School captain Sarah Haynes delivered her speech to the student body, as well as parents and teachers.

"It seems to me that today's schools are being run more and more like businesses, where everything becomes financially motivated," she said.

She received a standing ovation from her fellow students.

Ms Haynes said she wrote two versions of her speech — the one she took to the teachers and the other she actually delivered.

"I've given a fair few speeches in my lifetime but once I became school captain, everything I ever wrote had to be sent and censored by those higher up than me.

"I was never trusted to say the right thing, which I found kind of silly because if I wanted to say something audacious, like I am today, I could always have sent someone a different speech."

When the ABC made contact with Ms Haynes, she explained that she was about to board a flight for a family holiday and could not comment.

The ABC understands that the teachers have received a directive not to speak to the media.

School's 'obsession with money'

Ravenswood School for Girls in the Upper North Shore suburb of Gordon. ( Sardaka/Wikipedia )

Reverend Ian Powell was the chaplain at the elite boys' school Shore, also on Sydney's North Shore, for nine years.

He said students can be the victims of the private school's desire to enhance its brand.

"Of course they've got to be run as efficient businesses or they go broke, but the obsession with money and image and advertising, it was a problem back when I was serving at Shore with a number of the private schools, and it's a problem that only seems to have gotten worse."

He said schools fall into the hands often of lawyers and advertising gurus.

"That's how advertising works — shiny pictures of shiny kids, chosen because they're good looking.

"Scholarships given to sportsmen and musicians, really, to enhance the school's 'look at us, look at us'.

"Really all they're saying is look at how we've gone picking kids because of what they can do for the school."

Public education advocate Jane Caro is not surprised by Ravenswood's culture.

"The school's reputation, any school, it doesn't matter what kind of school it is, should never come ahead of student welfare, and of course of education," she said.

"And Sarah Haynes is completely right, no school is perfect, most schools are pretty good, but you don't need to pay $28,000 to get a decent education."

Reverend Powell said that with privilege comes responsibility.

"The headmaster when I was at Shore used to often say to the boys and the staff, 'to whom much is given, much is expected' — Jesus' words."

The school council's chairman, Mark Webb, told Fairfax that Ms Haynes' speeches had not been censored.

He said the school provides a safe and respectful learning environment.