The gay lifestyle is “unhappy" and the punishment for gay sex is death: these are among the messages in sermons delivered by evangelical churches that hold their services on public school grounds in NSW.

In one recorded sermon posted online by the Hunter Bible Church, based at Lambton High School in Newcastle, an unnamed pastor says: "Homosexuality is one of the things that send people to hell."

Another recording is from the Lakes Christian Church, based inside the Berkeley Vale Campus, Tuggerah Lakes Secondary College on the NSW Central Coast. It quotes the Bible's book of Leviticus, including references to the death penalty as a punishment for the "sin" of homosexuality.

The unnamed pastor tells his congregation: "In Chapter 20, He [God] states the death penalty for those who disobey. And notice throughout ... if it is not the death penalty, it’s being cut off from the people of God, which is still death, not just instant death and so God is serious about sexual purity.”

The sermons were not delivered to students during school hours, but to congregations on weekends when the churches lease school buildings.

However, in response to a complaint to Lakes Secondary College, acting principal Carlie Wells said the sermon was not appropriate.

"I have determined that the sermon described in your complaint was not consistent with the expectations of the community use agreement between Tuggerah Lakes Secondary College Berkeley Vale Campus and The Lakes Church," she wrote in response to the complaint by Darrin Morgan from Human Rights Advocacy Australia.

Ms Wells told Mr Morgan the school would review its arrangements for use of its facilities, although the church continues to run services at Lakes Secondary College.

A spokesman for the NSW Department of Education referred SBS to its policy for the use of school facilities: "The Department of Education does not allow any group or church to use school grounds to preach homophobic messages."

However, all of the churches denied the sermons were homophobic.

Pastor David Sheath from The Lakes Church said: "Views on sexual ethics differ in society. Our beliefs are those of mainstream Christian churches around the world. We teach that Christ offers life and hope in a world which lacks both."

The Hunter Bible Church sermon states homosexuality is wrong and against God’s will.

"Anything outside of that, whether it is homosexuality, or adultery or pornography or sex before marriage; anything that doesn't conform with what God created us into, is wrong," the pastor told his congregation.

Pastor Dave Moore from the Hunter Bible Church denied anti-gay sermons had been preached on the school site.

"No message that fits what you’ve described has been given on school grounds," he told SBS. When SBS drew his attention to the recordings about homosexuality on the church's website, Pastor Moore did not respond.

In an audio recording from the Maitland Evangelical Church, based at Maitland Grossman High School, Pastor Roger Burgess condemns incest, homosexuality and adultery in the same sermon.

"God does not want us sinking in a sea of shame," he said.

“If a man commits adultery with another man’s wife, with the wife of his neighbour, both the adulterer and the adulteress are to be put to death. Now that sounds drastic doesn't it and it is - God will judge sexual sin. The Israelites didn’t get away with it back then, and we will not get away with it either."

Maitland Evangelical Church did not respond to SBS' questions.

All the sermons have been removed from the churches’ websites since SBS contacted them.

The sermons are being delivered by members of the Fellowship of Independent Evangelical Churches. Many of them do not have their own churches so conduct their services on public school grounds, by arrangement with the individual schools.

In The Lakes Church sermon, the preacher states: "God’s good design for sex within marriage" is between "one man and a woman".

"Even though books have been written and studies have been conducted to show that the gay lifestyle is not a happy one, people persist in the rejection of God. Let me encourage you that if you are in any doubt about how destructive that sexual sin is ... have a look at the research and I can, I can point it out to you.”

Pastor Sheath from the Lakes Church said the sermon was specifically in relation to a talk on sexual ethics at the Festival of Dangerous Ideas and that it was being misconstrued when taken outside of that context. He said he believed the church was compliant with the department's guidelines.

"We believe that we comply with the conditions of our agreement to use school facilities," he told SBS.

Lakes Secondary College and Lambton High School did not respond to requests for comment. Maitland Grossman High School said it did not wish to comment.

Darrin Morgan, from the Human Rights Advocacy Australia complained to both the Department of Education and Lakes Secondary College in April this year. But he said other than asking the church “not to preach homophobic messages”, the department and school had taken no further action.

“HRAA believes that NSW public school facilities should not be used to promote beliefs which marginalise members of both the school and wider community,” he said.

Mr Morgan said religious groups with these views should not be using school facilities.

"HRAA is simply asking the Minister for Education and the Department of Education to implement the department’s own policies and procedures in an objective and neutral manner. This requires such organisations to be deemed 'inappropriate organisations' and therefore must be denied use of public school facilities.”