Before leaving for Beijing, Lee told reporters that summit talks between Moon and Chinese President Xi Jinping could take place on the sidelines of a Group of 20 meeting to be held in Germany in July and then again in time for Aug. 24 when both countries mark the 25th anniversary of building diplomatic ties.

"I will deliver such opinions (to the Chinese side)," he said.

Lee added that his trip to Beijing will place much emphasis on improving the frayed bilateral relations in such areas as personnel, the economy and tourism, which have taken the brunt of China's retaliatory measures against the THAAD installation on its soil.

"With regard to the THAAD issue, I will do my best to sufficiently explain President Moon's stance (to the Chinese side)," Lee noted.

The former South Korean prime minister was expected to meet with ranking Chinese officials, possibly including Chinese President Xi Jinping.

The special envoy's trip comes after Xi's invitation for Moon to visit Beijing during their telephone conversation last week.

During the long 40-minute call made by Xi, the Chinese leader explained reasons for Beijing's opposition against the THAAD deployment in South Korea, Cheong Wa Dae officials said earlier.

Moon said he understood China's position but noted many South Korean people and businesses in China were suffering from China's apparent economic retaliation against the deployment, asking Xi to personally look into ways to resolve the issue.

Apparently highlighting the importance he places on Seoul-Beijing ties, Xi earlier met with a South Korean delegation to an international forum held in Beijing.

Park Byeong-seug, a lawmaker from the ruling Democratic Party and head of the South Korean delegation, later noted the phone conversation between Moon and Xi appeared to have "triggered a mutual consensus on repairing South Korea-China relations."

The special envoy Lee's discussions were also expected to include ways to deal with increasingly provocative North Korea as his trip also follows the North's launch of an intermediate range ballistic missile that has prompted fresh condemnation from the UN Security Council in a statement backed by all Security Council members, including China.

President Moon has said he will utilize all available means, including dialogue, to rid North Korea of its nuclear weapons, but that talks were possible only under the right conditions.

Lee is the third special envoy of the new South Korean leader to visit a foreign state. Moon and his special envoys have said their job was to relay Moon's personal message to his foreign counterparts, and letting them know what he planned to do with his country and North Korea.

Later in the day, a special envoy for the European Union and Germany embarked on his trip, which is expected to focus on sharing the president's willingness to consolidate ties with European countries.

A special envoy to Russia is expected to head to Moscow next week. Moon has also named a special envoy to the Vatican. (Yonhap)