Speaking to journalists today, Dr Jong-wha Park of the assembly organising committee stressed that the next assembly would bring together not only WCC members, but the representatives of other Christian traditions, including Pentecostals and Evangelicals still outside the WCC fold.
"Moving together towards a wider Christian family, a wider global Christian forum, that is our goal and we are moving towards this goal," he said.
"That's why Pentecostals are invited, evangelicals are invited, ecumenicals are invited to Korea. This is the clear sign that we are working towards a wider ecumenical solidarity."
Dr Oh Sung Kwon, of the National Council of Churches in Korea, added: "Not only Korean churches but all of the Asian churches will work together. Especially the Korean churches – the ecumenical, evangelical, Pentecostal – all of us will do our best for a faithful assembly."
While the WCC counts some Pentecostal and evangelical churches among its membership, closer relations with the wider Pentecostal and evangelical traditions have been prevented by differences in approach to mission, social action, and scriptural authority, particularly in relation to sexuality.
Douglas Chial, WCC staff member and part of the visiting team to each of the candidate venues, stressed that evangelical and Pentecostal churches were among those inviting the WCC to Busan.
He said: "In the past we have seen a growing participation of Pentecostal and evangelical churches in the assembly at the invitation of the Central Committee and now we are preparing for an assembly in a context where those churches are part of the inviting body of Christ and that's very new in the life of the WCC. So there are many new possibilities in this assembly."
Dr Park added that in South Korea, the Pentecostal, evangelical and ecumenical churches enjoyed good relationships at the local and regional levels.
The best scenario, he said, would be create an assembly that went "beyond ecumenical and evangelical distinctions".
"This is highly possible," he said.
Dr Park went on to express his hope that the assembly would offer an open forum for Christians from North and South Korea to come together.
"This time in 2013 they (North Korean Christians) are surely invited," he said. "I do hope that before you come to Korea in 2013, Korea can be united – that is our wishful thinking!"
The church in North Korea has been invited to send a delegation to every General Assembly since the WCC met in Canada in 1983.
Dr Park said the WCC planned to hold preparatory meetings in North Korea in the run up to the next assembly.
The assembly planning committee will now get to work on proposals for the theme of the next General Assembly. Mr Chial said the proposals would be formulated in close cooperation with the churches in South Korea and probably voted on at the next meeting of the Central Committee meeting.
Dr Park said spiritual unity and social action would likely influence the theme, while Dr Kwon said he would like to see peace mentioned.