South Korean President Park Geun-hye is to meet with Chinese President Xi Jinping this month in Beijing. Yun told lawmakers Tuesday the word "denuclearization" could be added to a joint declaration that is expected from the meeting.
"One of the top priorities among South Korea, the U.S. and China is the denuclearization of North Korea," he was quoted by the Yonhap News Agency as saying.
North Korea last weekend proposed direct talks with the United States over nuclear security concerns. The South Korean and U.S. governments said they doubted the sincerity of the proposal.
U.S. State Department spokeswoman Jen Psaki said Monday that the U.S. government would consider meeting with North Korea under the umbrella of a multilateral framework.
"The key piece here is that they need to take credible steps to move toward concrete denuclearization," she said.
Multilateral nuclear talks among the two Korean governments, the United States, China, Japan and Russia ended in 2008. North Korea has conducted three nuclear tests since then.