Sydney Anglicans are being warned not to rely on the newly elected Pope Benedict XVI as their champion, despite an overwhelming endorsement of his conservative Christian agenda.

Writing in her upcoming Southern Cross column, Ms Rodgers says many Sydney Anglicans would welcome the news that the new Pope would stand against the Western secularist agenda.

This week, Pope Benedict XVI warned the Roman Catholic Cardinals to stand firm against "the dictatorship of relativism'.

US evangelicals, such as Chuck Colson, have given a glowing endorsement of Cardinal Ratzinger as he becames Pope saying he ‘is a great choice’. They expect the hard line on issues such as homosexuality, abortion and euthanasia to be maintained.

However Ms Rodgers, a member of the Anglican Church’s ecumenical working group, says the sentiments of the Declaration Dominus Iesus that the then Cardinal Ratzinger authored in 2000, should concern Bible-believing Christians.

"Dominus Iesus contains clear affirmation of Jesus Christ and Scriptural quotes about his person and work. Yet, biblical Christians can't agree that salvation through Christ can be found in the Catholic Church only," she writes.

Bishop of South Sydney Robert Forsyth told AAP that Pope Benedict XVI would “seek and defend the Christian truth”.

He says he respects the Pope’s belief that other Christian churches have “defects”.

“What else would you expect a Roman Catholic to say?” Bishop Forsyth said.

“I happen to think the same about his church.”

“But I respect the simple straightforwardness of this. That’s the kind of teaching of God we need and I’m delighted to hear it.

“This concept of no wavering from what God has given us (I support), even though we might disagree about some of the detail.”

Margaret Rodgers’s column will be published in the May issue of Southern Cross.