"This will be Kobia's first meeting with the head of the Roman Catholic Church since he became WCC general secretary in 2004," the grouping representing most of the world's Orthodox and Protestant churches said in a statement on Friday.

The Catholic Church does not belong to the WCC, but it has members on some of its bodies, including its Faith and Order Commission, which seeks to bring churches into theological dialogue to promote church unity.

Vatican official Bishop Brian Farrell, who is secretary of the Pontifical Council for Promoting Christian Unity, last week described the WCC as an "essential partner" in the ecumenical movement.

"But," noted Farrell, "it is no secret, I think, that we have had criticisms of the WCC that are also shared by some others." He urged the strengthening of the church grouping's work on Faith and Order.
 
"When Faith and Order was central to the life of the World Council, we believe that the organization was more effective as an instrument in the quest for Christian unity," said Farrell, during a 9-16 May WCC meeting in Athens.
 
After Benedict's election in April, Kobia said he hoped the new Pope would "initiate new ways of cooperation between the Roman Catholic Church and the World Council of Churches".

In the early 1970s, Benedict, then German theology professor Joseph Ratzinger, was a member of the WCC Faith and Order Commission.

Later he was the first Catholic co-chair of a Catholic-Protestant commission in Germany which helped pave the way for a global Catholic-Lutheran agreement on the doctrine of justification, a key divisive issue at the time of the Reformation.

Still, as the Vatican's guardian of doctrine, Cardinal Ratzinger reaped criticism for a 2000 statement which said Protestant denominations were not "churches in the proper sense".

After being elected Pope, Benedict said, however, he wanted to promote Christian unity.
 
"We are full of hope in everything we've heard regarding ecumenical relations," said Farrell. "The Pope is totally supportive."