But some parents are calling for greater oversight, and said there was no place for these groups in secular schools.

The Planetshakers are running breakfast, girls empowerment and anti-bullying programs in 20 Victorian schools.

Volunteers put on events where Christian hip hop artists perform. The group also offers mentoring and sports activities.

Kids Hope – whose slogan is "one child, one hour, one church, one school" – runs mentoring programs, while Christians Helping In Primary Schools (CHIPS) runs anti-bullying, anger management and anxiety seminars for students and staff.

Rosalie Crestani, the deputy leader of anti-Islamic party Rise Up Australia and a City of Casey councillor, volunteered with CHIPS for three years.

The group also organises camps for primary school students who have experienced trauma. The camps are promoted by schools and take place "in a caring, Christian environment" with the student's parents.

Lara Wood, the spokeswoman of lobby group Fairness in Religion in Schools, said churches knew schools were stretched and reluctant to turn away help.

But Ms Wood said she was concerned about the groups' motives.

"They are free to proselytise and the [Education] Department is not aware of what is going on. They have flown under the radar and have a free run in the schools," she said.

She called for stricter vetting of groups that work in schools.

"There is no third-party checking to see if these people are qualified to counsel at-risk children who may have psychological issues," she said.

Former pastor and now Access Ministries spokesman Rob Ward said churches had always been involved in community service and it was part of the "Christian ethos".

"There's a perception that they are in there for some ulterior motive but they are not after anything," he said.

Planetshakers chief manager Nicole Yow said demand for the church's student services was increasing.

"We've noticed that bullying has become a bigger social issue compared to what it was four years ago," she said. "We are greatly concerned about this emerging trend."

But she said that religion was never discussed during the programs.

CHIPS co-founder Cathy Wieckmann said schools requested the programs, which helped students who had experienced trauma, grief or loss.

"Schools know we are a Christian organisation, but we don't promote religion in schools," she said. The organisation also provides chaplains in 16 primary schools.

Parents Victoria executive officer Gail McHardy said schools needed to scrutinise groups that received access to their students.

"We would expect that any extra-curricular activity only occurs after an outline of the program is provided to parents, and with written parental permission," she said.

One parent, who did not want to be named, said she was shocked to discover that CHIPS volunteers were helping out with literacy programs at her son's school. "It concerns me that people from a religious organisation are working in a secular state school without formal consent from parents," she said.

An Education Department spokesman said content delivered by guest speakers must be secular.

"Religious organisations may provide services like chaplaincy, but these should also be secular in nature and should not promote external events run by their organisation," he said.

It follows the Andrews government scrapping special religious instruction from the curriculum, with the 30 minute program now moved to lunchtime and before and after school.

Ben Stephenson, the chaplain at Forest Hill College, said the Planetshakers' anti-bullying program sent a positive message to students.

"We had a fair bit of discussion to ensure that it was very secular in nature," he said.

"We looked at the content beforehand to make sure it didn't overstep any boundaries."

He said the school paid for the program.