One of the largest evangelical Christian organisations on US college campuses has told its staff – around 1,300 of them – that they will be fired if they support gay marriage, according to Time Magazine.

InterVarsity Christian Fellowship USA has branches in 667 US colleges. It produced a position paper on human sexuality in March last year advocating a tradition view of same-sex relationships which saw them as contrary to Scripture. The paper says: "Scripture is very clear that God's intention for sexual expression is to be between a husband and wife in marriage. Every other sexual practice is outside of God's plan and therefore is a distortion of God's loving design for humanity." IVCF invited staff to study the paper and explore its conclusions.

According to TIME, the organisation has said it will start a process for "involuntary terminations" for any staff member who disagrees with its positions on human sexuality. While they are not being asked to sign a document agreeing with the group's position, they are being asked to come forward voluntarily. When they inform their supervisor of their disagreement, a two-week period is triggered.

IVCF vice-president Greg Jao told TIME in an email: "We internally categorize these as involuntary terminations due to misalignment with InterVarsity ministry principles, which is a category we use for people who leave for theological and philosophy of ministry disagreements.

"Our goal is not to go, 'Oh we want you to do the dirty work of firing yourself,' I think our thing is, if you are in disagreement, then we are going to ask you, with integrity, to identify that and leave," he added in an interview.

IVCF responded in a series of tweets: "Sadly @elizabethjdias' @TIME article is wrong.

"We have no policy on employee views on civil marriage. We lament that LGBTQI people have experienced great pain, including much caused by Christians. We also know that we ourselves each need Jesus' grace daily. So we attempt to walk humbly in this conversation.

"We do hold to an orthodox view of sexuality and Christian marriage, as you read in our Theology of Sexuality Doc at bottom of article. We believe Christlikeness includes embracing Scripture's teachings on human sexuality—uncomfortable and difficult as they may be AND Christlikeness demands we uphold the dignity of all people, because we are all made in God's image.

"Some will argue this cannot be done. We believe that we must if we want to be faithful followers of Jesus. Within InterVarsity and elsewhere, some LGBTQI people agree with this theology, at great personal cost. We are learning together."

IVCF has been approached for comment on this story.