THE state government will boost funding to Christian education classes in schools in the budget, with Education Minister Martin Dixon ruling out changes to the controversial program.

Mr Dixon said Christian education provider Access Ministries would receive an extra $200,000 a year from July 1 for training, administration and the supervision of volunteer instructors.

While other courses, including Baha'i, Greek Orthodox and Islamic, are also accredited, Access Ministries runs 96 per cent of special religious instruction classes in Victoria.

The funding boost comes as Access Ministries called on Christians to take urgent action, saying its very foundation was being challenged by a court case that questioned the Education Department's guidelines on the teaching of faith in schools.

The agency called on Christians to write a letter of support for special religious instruction to Mr Dixon, Premier Ted Baillieu and their local MP.