A South Australian politician has complained that her daughter’s pre-school is teaching children about gay marriage.

Sarah Game said her four-year-old had returned from pre-school to say ''girls marry girls and boys marry boys”.

“Kids this young shouldn't be taught such concepts at school. Leave it up to parents - who know best - to decide,” she said.

Sarah Game, a mother of three, is a former veterinarian who was elected to State Parliament this year for One Nation.

“I believe parents should be front and centre of teaching children moral and ethical issues, not teachers,” Game said.

“Primary school children need to be taught love and acceptance of others, which is enough detail for their age.”

Game told the South Australian Parliament this week that she had spoken to multiple parents who were concerned about schools promoting LGBTQ ideology to children.

She said she had met with parents “who have a child on this journey” to gender transition and were distressed that schools automatically affirmed their children in that decision.

“They feel excluded from investigating anything other than an affirmation pathway,” she said.

Education Department guidelines issued to all South Australian schools and pre-schools state that “diversity is valued” and that they must provide “an inclusive learning environment where intersex and gender diverse children and young people know they belong”.

A report in the Daily Mail said the education department now directed schools to support and help children who “might want to affirm a gender identity that is different from their assigned gender at birth”.

The guidelines state that, in the case of a disagreement with parents over gender affirmation, school principals should decide what is in the “young person’s best interest”.

If a school principal determined that it was in the child’s interests to transition away from their biological sex, even against the wishes of parents, then the principal was to go ahead and “make support arrangements” for the child.