Chinese and South Korean lawmakers are expected to establish a communication channel to help improve ties that soured two years ago after South Korea agreed to install a US anti-missile system that China regards as a national security threat.

Seoul will send a 20-man bipartisan delegation led by Representative Park Byeong-seug of the ruling Democratic Party to Beijing on Tuesday for a five-day visit, South Korea's Yonhap News Agency reported on Sunday.

The South Korean officials will meet with leading Chinese parliamentary officials and representatives of the Communist Party of China to discuss issues of mutual concern, including North Korea's nuclear and missile programs and cooperation in the security and economic fields, the report said. 

The trip will establish a communication line between the South Korean National Assembly and its Chinese counterpart, the National People's Congress, which is crucial for improving bilateral ties, Lü Chao, a research fellow at the Liaoning Academy of Social Sciences, told the Global Times on Monday.

The South Korea lawmakers' visit comes in the wake of South Korean President Moon Jae-in's state visit to China in December 2017, during which the two countries' heads met and agreed to resolve the nuclear issue through dialogue and negotiations.

Seoul's lawmakers will also brief Beijing on the inter-Korea talks held last week, in which high level officials from North and South Korea discussed Pyongyang's participation in the upcoming Winter Olympic Games in PyeongChang, Lü said.

China and South Korea saw their ties frayed in recent years over the deployment of the Terminal High Altitude Area Defense (THAAD).

The two countries announced a deal in October to normalize bilateral relations.

Since the THAAD issue has not been properly handled by South Korea, Chinese citizens remain cautious of traveling to South Korea.

Seoul officials are likely to promote cooperation on tourism as the Chinese New Year holidays are just around the corner, said experts.