More than 100 teachers at the elite Sydney girls' school, Kambala, signed a motion of no confidence in the former principal, Debra Kelliher, and scores of parents urged the school council to take action before Ms Kelliher resigned on the first day of the school holidays.
The school council, headed by prominent businesswoman Sally Herman, wrote to parents on Monday to tell them Ms Kelliher had resigned effective immediately after doing a "wonderful job" at the Rose Bay school during her 3½ year tenure.
But parents and teachers who have contacted Fairfax Media said they were "appalled" by the glowing statement from Ms Herman and said it was "grossly inaccurate" to suggest Ms Kelliher had performed well at the school.
In a letter from the Kambala Parents' Association circulated among families last week, parents were urged to contact Ms Herman with their concerns.
The letter said the school had lost 135 staff members in three years and the "gross unhappiness of the majority of the staff" meant many more were planning to leave.
"All of these people have put their careers and livelihoods on the line in an effort to be heard," the letter, dated April 7, said. "Surely it is an embarrassment to all of us in the community that Kambala treats its most prized asset, its teachers, so appallingly that they felt the need to do so. More embarrassing still if nothing is done to rectify the situation immediately."
It is understood the school disputes that the level of staff turnover is excessive and maintains it is lower in 2016 than the average turnover for independent schools.
A former teacher, who asked to remain anonymous, said Kambala had been a "fun, supportive place to work".
Another teacher who is still at the school said some staff "lived in fear of losing their job".
Fairfax Media has attempted to contact Ms Kelliher and Ms Herman has been asked to respond to the claims.
One of the parents who contacted Fairfax Media said there was intimidation and bullying at the school but the teachers were prepared to take a stand.
"Through their actions, the teachers have taught the students to speak the truth and to stand up for what's right. The parents are extremely grateful to the dedicated staff of Kambala who have have put the wellbeing of their students above their own interests,'" the parent said.
"What the council has done in sending that statement is an absolute travesty because there have been really long-serving teachers who have left the school because of the principal and the council still planned to keep her."
While many parents have been angered by the treatment of teachers, one parent told Fairfax Media that some parents had been "shocked" to hear that Ms Kelliher was unpopular.
"It's very surprising to all the parents we know both in the junior school and senior school as they are very pleased with the principal and the changes she has made, as well as massive improvements in HSC results under her leadership," the parent said.