The South Korea-based Chinese company Maofa International Travel Service is the exclusive agent of South Korean business people who apply for multi-entry visas, state-run Global Times quoted reports as saying.
Many South Koreans were reportedly refused long-term business and exchange-based visas following the decision to deploy the Terminal High-Altitude Area Defence (THAAD) system in South Korea.
South Korea's foreign ministry said it will "analyse" whether the move is related to Seoul's deployment of THAAD.
Both US and South Korea said the THAAD deployment was to counter missile attacks from North Korea.