South Korean authorities are negotiating with China to restore the service.
South Korea said that Chinese authorities have blocked popular messaging apps KakaoTalk and Line saying that the apps are being used for circulating terrorism related material.
The Chinese authorities have given their first explanation for blocking the services a month ago, according to South Korea's Ministry of Science, ICT and Future Planning.
Reuters quoted the South Korean ministry as saying: "The ministry will continue negotiations with relevant Chinese counterparts to ensure that service disruptions for KakaoTalk and Line as well as inconvenience for the users in China are resolved as early as possible."
China informed the South Korean ministry that terrorist organisations were spreading information how to make bombs through the messaging channels, hence they were not safe.
China has also blocked Talk Box, Didi and Vower.