Dr Michael Nazir-Ali wants to uphold traditional teachings of the Bible
A traditionalist Anglican group has warned the issue of homosexuality could split the Church of England the way the Episcopal Church has done in the US.
The Fellowship of Confessing Anglicans will be launched in the UK on Monday.
The group has campaigned against active homosexuality in the Anglican Communion after being established last year.
One supporter, the Bishop of Rochester, the Right Reverend Michael Nazir-Ali, told the Sunday Telegraph homosexuals should "repent and be changed".
The fellowship was set up at a conference of conservative Anglican bishops and leaders in Jerusalem in the wake of the ordination of an openly gay bishop in New Hampshire, and includes a breakaway Anglican Church in the US.
It promotes a traditionalist reading of the Bible which outlaws active homosexuality.
BBC religious affairs correspondent Robert Pigott says the group constitutes a powerful lobby inside the communion to campaign against both the ordination of gay clergy and the blessing of same-sex relationships in church.
The fellowship has already helped to unite traditionalist American congregations who left the Episcopal Church into a small separate Church.
The group has warned that if what they claim is the Church of England's liberal drift continues it is likely to face a similar split.
The breakaway Church in the US began as traditionalist congregations invited bishops from outside the country to oversee them.
It is a step English traditionalists have warned they might also be prepared to take.
Ahead of the group's UK launch, Dr Nazir-Ali told the Sunday Telegraph: "We want to uphold the traditional teaching of the Bible. We believe that God has revealed his purpose about how we are made.
"People who depart from this don't share the same faith. They are acting in a way that is not normative according to what God has revealed in the Bible.
"The Bible's teaching shows that marriage is between a man and a woman. That is the way to express our sexual nature.
"We welcome homosexuals, we don't want to exclude people, but we want them to repent and be changed."