The Brisbane school made national headlines this year over the contracts, which stipulated it would only enrol students on the basis of the gender that corresponds to their biological sex.

It also said homosexuality is "sinful", like bestiality, incest and pedophilia.

The school eventually withdrew the contracts and principal Brian Mulheran stood aside in February.

Parents and former students of the college have announced plans to file discrimination complaints with the Queensland Human Rights Commission, and will gather outside state parliament on Thursday.

"When I read the contract put out by Citipointe I was heartbroken that the identity of my daughter Emmey, and others like her, would not be recognised and supported by the school," Janina Leo, the mother of a former student said.

"I had no choice but to remove my children from Citipointe as I would not sign a contract that supported discrimination against my own child and other LBGTIQ+ children."

The complaints are being supported by the Queensland LGBTI+ Legal Service.

"Our clients have suffered greatly due to these actions, and these children will bear the scars for many years to come," the service's Matilda Alexander said.

The matter had been referred to the Non-State School Accreditation Board before the contracts were withdrawn, and caught the attention of the state's Human Rights Commission.

"A school policy that requires a trans or gender diverse young person to be treated as their sex assigned at birth, or that requires a young person to hide or deny their sexuality, is likely to amount to unlawful discrimination," it said.

Citipointe has been contacted for comment.

Australian Associated Press