Parents say non-religious children as young as six have been handed advertising material from Christian scripture providers telling them "we were created by a loving God", prompting apologies from a number of schools and the NSW Department of Education.
Helen Brady, whose six-year-old son attends a public school in western Sydney, said she found a brochure published by the group Christian SRE in his backpack, despite stating he subscribed to "no religion" on his school enrolment form.
"I immediately asked him who handed him this brochure and was told it was given to him by our year 1 teacher," Ms Brady said.
"My child attends our local public school ... we didn't wish for him to take part in any religious education at school.
"You can understand then, having made this decision on his enrolment form 18 months ago, why I was surprised and angry that I was being further promoted to."
Ms Brady said she emailed NSW Education Minister Rob Stokes and the school's principal.
"The school acknowledges that sending the SRE flyer was an oversight," she was told in a letter from the NSW Department of Education on behalf of Mr Stokes.
"The school apologises for any distress this may have caused you or your family."
We didn't wish for him to take part in any religious education at school.Helen Brady, parent of a Year 1 child at public school in western Sydney
Mr Stokes told a budget estimates hearing on Friday that he had not been told of any such incidents but that he would find them concerning.
"I would be concerned if that were the case, if material of any kind had been forced on students against their will, in light of the fact that it's a parent's choice to opt out," Mr Stokes said.
Ms Brady said the principal also apologised and said the pamphlets were accidentally sent out to all classrooms by temporary office staff.
"Luckily my son didn't read the brochure as it contained phrases such as 'Christian SRE begins with the understanding that we were created by a loving God, who calls us to fullness of life'," Ms Brady said.
A spokesman for the department said both SRE and Special Ethics Education groups have distributed informational pamphlets to inform parents about changes to procedures that will be implemented next year.
"The approved providers have requested that schools make these pamphlets available in enrolment packs and the school office and for the SRE and SEE co-ordinators to be able to distribute the relevant pamphlet to students in their SRE/SEE class," the spokesman said.
Christian SRE said it printed 760,000 copies of the brochures and sent them to schools at the end of last month.