South Korea's top nuclear envoy left for China on Tuesday for a five-day visit to discuss ways to resume the long-stalled six-party talks on denuclearizing North Korea, Seoul officials said.

The six-nation negotiations, involving South Korea, North Korea, the U.S., China, Russia and Japan, have been dormant since late 2008 when the North walked away from the negotiating table.

Pyongyang conducted nuclear tests in 2006, 2009 and 2013.

Hwang Joon-kook, special representative for peace and security affairs on the Korean Peninsula, will hold talks with his Chinese counterpart, Wu Dawei, in Beijing on Friday, during which they will likely discuss how to reopen the stalled six-party talks, the foreign ministry said.

His visit comes about four months after the two nuclear chiefs held such meetings in Beijing.

"(The two sides) plan to assess North Korea's nuclear issues and will discuss extensively how to respond to problems down the road, including the North's advancement of its nuke capabilities,"

Hwang told Yonhap News Agency by phone before departure for China. 

Hwang's itinerary includes a rare trip to the northeastern Chinese city of Shenyang, where on Tuesday he is scheduled to meet with Chinese experts from various sectors, including researchers on issues affecting the Korean Peninsula.

China's northeastern provinces are home to thousands of North Korean defectors waiting to come to South Korea. It is the first time for a South Korean top nuclear envoy to visit such provinces containing border towns with North Korea.

Hwang's planned visit to Beijing is likely to coincide with a trip by Sydney Seiler, the U.S.'s No. 2 nuclear envoy.

Seiler arrived in Seoul on Monday on the first leg of his three-nation tour that will also include stops in Beijing and Tokyo.

The U.S. envoy plans to have talks with his South Korean counterpart, Shin Chae-hyun, on Wednesday about the North Korean nuclear issue before flying to Beijing a day later. (Yonhap)