The Archbishop of Canterbury is facing criticism from fellow Anglicans over his comments on Islamic Sharia law.
Dr Rowan Williams is still caught in the eye of the Sharia law storm
Archbishop Gregory Venables, primate of a group of Anglican dioceses in South America, said confidence in Dr Rowan Williams's leadership had plummeted.
Dr Williams's predecessor Lord Carey has also weighed into the row, saying the acceptance of some Muslim laws would be "disastrous" for Britain.
Supporters of Dr Williams say reaction to his comments has been "hysterical".
Dr Williams sparked a major row after saying, in a BBC Radio 4 interview last week, that the adoption of parts of the law was "unavoidable" in Britain.
Despite attempts to clarify his comments and support from both within and outside the church, controversy continues to surround Dr Williams.
On Monday, he will face the Anglican Church's national assembly - the General Synod - when it gathers for the body's biannual meeting. There is a chance a motion could be tabled to discuss the issue.
Dr Williams has insisted he was not advocating a parallel set of laws but has faced calls for his resignation.
BBC News religious affairs correspondent Robert Pigott said it was "inconceivable" that Dr Williams would be forced to quit, adding the Archbishop was held in "deep affection and respect" by rank and file Anglicans.
Church 'deeply split'
He said the long-term problems might lie abroad in the Anglican communion.
"The international church is already deeply split over the issue of homosexuality," he said.
"Many Anglicans in Africa and Asia live side-by-side with Muslims and for them Sharia is a sensitive issue.
"Dr Williams's remarks have damaged his personal authority."
Archbishop Venables is Primate of the Southern Cone, which is made up of seven dioceses across South America.
He said Dr Williams's comments were a "surprise".
"Taken within the context of other things that have been said and done in recent months, it will just add to the general sense that confidence in the leadership of the Anglican Church has plummeted," he said.
Confidence in Dr Williams has also been eroded at home, with criticism from the church's former leader Lord Carey.
Sharia law is Islam's legal system
It is derived from the Koran and the life of the prophet Mohammed
Sharia rulings help Muslims understand how they should lead their lives
A formal legal ruling is called a fatwa
In the West, Sharia courts deal mainly with family and business issues
English law recognises religious courts as a means of arbitration
He flatly contradicted the Archbishop's suggestion that the law should incorporate elements of Sharia.
But writing in the News of the World, Lord Carey said his successor should not be forced to quit.
Alun Michael, former Home Office minister, accused Dr Carey of being "disloyal" and condemned what he called the "absurd media feeding frenzy".
He told BBC Wales' Politics Show: "If the reportage in the press is hysterical, inaccurate and inflammatory then it's very difficult for those who are asked to comment on it to deal with it properly."
Since making the remarks in a lecture to lawyers and in the BBC interview, Dr Williams has produced both anger and agreement from politicians, religious leaders, the public and people within his own church.
At least two General Synod members have called on him to resign.
Catholic leader Cardinal Cormac Murphy-O'Connor is one of the many to come out in defence of Dr Williams.
"I feel he may fear that people with a Christian conscience will be put to the sidelines and not allowed to say what they believe to be true for the common good," he told the BBC.