The Victorian Education Department forces primary schools to run the classes if an accredited religious instructor is available, although parents can choose to opt their children out.

However, a survey by lobby group Fairness in Religions in School reveals only 28 per cent of schools in Melbourne's west provide special religious instruction, compared with more than 87 per cent of schools in the eastern suburbs.

Click here for a larger, more interactive version of this map

The survey comes as three parents today commence legal action in the Victorian Civil and Administrative Tribunal, alleging that the Education Department segregates children on religious grounds and discriminates against those whom parents opt out of the classes.

One of the parents, Sophie Aitken, says in her complaint her children were put in the corridor or given Lego to play with when she opted them out of special religious instruction at Ivanhoe East Primary.

''I am troubled by this segregation and the limitations it causes my children … Once [my son] was told by another child that he would go to hell because he didn't believe in God,'' she says.

Yarraville West Primary is one of 71 state primary schools in Melbourne's western suburbs that does not offer special religious instruction.

School council president Lisel Thomas says the school is relieved it has never been approached by an accredited instructor and therefore is not compelled to hold the classes under the contentious Victorian legislation. ''We have raised the issue of how we would feel if we were approached and basically told we had to deliver special religious instruction without us having a choice in the matter and that certainly concerned our school council,'' Ms Thomas said. ''We have children from a number of different religious backgrounds. We believe it is important for children to stay together and learn together rather than being segregated on the basis of their religious belief.''

About 96 per cent of special religious instruction in Victoria is provided by Christian organisation Access Ministries, whose volunteers run the classes in 850 of the state's 1300 government primary schools.

Access Ministries CEO Evonne Paddison said the VCAT hearing had been brought on by a ''small, secularist group, predominantly inner-urban, who want to impose their views on the rest of the community''.

''Their claim that special religious instruction forces religion on children is a myth designed to scare the community,'' Dr Paddison said. ''Special religious instruction enjoys broad community support.''

The Fairness in Religions in School survey found 311 primary schools in Melbourne held Christian classes, 53 offered a choice of Christianity or another religion, five offered a non-Christian option only and 216 did not hold the classes.

Monash University sociology professor Gary Bouma was unsurprised by the survey's findings. He said while schools in the eastern suburbs had a long history of providing special religious instruction, the resistance movement, spearheaded by Fairness in Religions in School, was also coming out of the eastern suburbs. ''As British Protestantism recedes in hegemony within Australia, rising in voice are some of the non-religious voices saying this stuff has no place in our schools.''

Access Ministries spokeswoman Denise Nicholls said religious instruction was run by locals. She said she expected programs run by other faith providers to increase in the culturally diverse western suburbs if their communities requested it, which was ''entirely appropriate''.