"The raid isn't directly related to Google but to an app development company," said Seonghun Kim, detective inspector with the Seoul Metropolitan Police Agency's Cyber Terror Response Center.
The company that developed the app is a subsidiary of Google, and it illegally collected location information from subscribers who installed the app, he added, in an apparent reference to AdMob, the mobile advertising platform that Google acquired last year.
Cybercrime officers carried out the raid at Google Korea's head office to secure hard drives and computer data related to Google's AdMob platform, Yonhap News Agency in Seoul reported.
Google had no immediate comment on the raid.
The subsidiary allegedly collected personal data with a smartphone application, the police agency said in an emailed statement.
Police will give further details on the case only after it progresses, Kim said.
Google has already come under fire in South Korea twice this year.
In January, authorities found that Google had illegally collected personal data while gathering information for its Street View map service. Google's data collection for this service has also raised privacy concerns in some European countries.
Google came under fire again in South Korea last month after two local search engine operators, Daum and NHN, filed a claim with the country's Fair Trade Commission, alleging pressure on Android phone manufacturers to block rival search engines or applications.
