The issue concerns the ordination of the first openly gay bishop, the Rt. Rev. Gene Robinson, to the Episcopal Church in New Hampshire.
On BBC television Sunday, two of those preparing to attend the summit were divided over the issue.
Speaking from Argentina, Archbishop Greg Venables said the church is like "two ships going in different directions."
He said the archbishop of Canterbury, the Most Rev. Rowan Williams, was right not to be too optimistic about avoiding a split in the Church.
His views were countered by Archbishop Njongo Ndungane, Primate of South Africa, who said the church was able to contend with the "creative diversity." He said "fragmentation" is not the way forward.