The Korea Communications Commission said Facebook also criticized Facebook's handling of personal information, provision of personal information to third parties and the social-networking site's privacy policy.
"Facebook violates the regulations on protection of privacy in information networks," said Choi Seong Jin, a spokesman for the KCC.
The U.S.-based company has 30 days to respond to the complaint, the KCC said.
Article 22 of South Korea's "Act on Promotion of Information and Communication Network Utilization and Information Protection" states: "If an information and communications service provider intends to gather user personal information, they shall obtain user consent."
The complaints come as Facebook is gaining popularity in South Korea. It has about 2.3 million members in the country, which accounts for roughly 5 percent of the population, according to figures from the KCC.
Just under two thirds of Koreans use social-networking services, the KCC said. Among citizens in their 20s that number rises to almost nine out of ten people.
South Korea is one of the most wired countries in the world and most homes enjoy fast, cheap, fiber-optic broadband connections.
