Hindu, Buddhist and Islamic scripture classes are growing rapidly in NSW public schools, and students are on waiting lists for the popular ethics classes.
But as the popularity of the religious and ethics classes grows, some academics argue that segregating children based on religious faith, or for other classes, has detrimental effects and is at odds with the inclusive philosophy of public education.
Ethics classes, which started in 2011, had about 13,000 students this year, up from 8000 12 months ago.
About 250,000 students in NSW public schools get Christian religious education, with the largest providers coming from Catholic and Anglican churches.
The NSW Islamic scripture program teaches more than 22,000 Muslim students, up from 17,000 at the end of 2010. The number of students taking Hindu dharma classes has doubled in the past five years and is fast approaching 10,000. Judaism classes are attended by 2700 students.
Southern Cross University sociology of religion expert Cathy Byrne says segregation on religious grounds is outdated, inappropriate and educationally unsound.
''International research has shown children learn best about these ideas when they are given the opportunity to dialogue with others of their own age,'' she said.
Dr Byrne said ethics classes have ''a fine and worthy intention'' but ''even if you have a school that has ethics volunteers, you can still get the outrageous distribution of inappropriate fundamentalist and proselytising material'', she said.
A push to abolish religious education in public schools is gaining momentum in Victoria, where Fairfax Media revealed children at one primary school were given a magazine that claimed girls who wore revealing clothes were inviting sexual assault, and homosexuality, masturbation and sex before marriage were sinful.
Macquarie University academic Marion Maddox says lessons about religion should be taught in a multi-faith setting and not by volunteers.
''For most children in public schools, the moment they get divided up on the basis of religion would be their first experience of being segregated on the basis of some social marker, and the fact it is happening at our public schools which are supposed to be about inclusivity is something we need to rethink,'' Professor Maddox said.
Rouba Kodr, who manages the Islamic program, says school scripture is an important service for parents who may not have the time to educate their children or the money to send them to religious school.
The deputy chair of the Inter-Church Commission on Religious Education in Schools, which represents Christian providers, Peter Adamson, said some parents could feel ''incompetent'' teaching their children about religion.
''Parents are concerned for their children's values and they may make a choice to expose their children to a faith which they at least nominally espouse,'' Mr Adamson said. ''Some parents feel incompetent to expose their children to the stories of whichever faith they belong, and they look to a faith community to do that for them.''
The commission's executive director, Sue Sneddon, said the growing number of religious and ethics providers has had ''a bit of an impact'' on enrolments, but it was difficult to determine to what extent.