A trip by Pope Francis to North Korea is "a dream that can be realized" and would be a gigantic step towards peace on the Korean peninsula, a senior South Korean bishop said on Thursday.

The bishop, Lazarus You Heung-sik of Daejeon, spoke ahead of a meeting next week in the Vatican between Francis and South Korean President Moon Jae-in, who will be carrying an invitation from North Korean leader Kim Jong Un to visit Pyongyang.

"If the pope goes there, it will be a gigantic step, a qualitative step for the Korean Peninsula, for its pacification," said You, who was in Rome for a meeting of bishops from around the world known as a synod.