South Korea's Fair Trade Commission (FTC) raided the offices on Tuesday as part of its probe into a claim by the country's major portals that Google is blocking Android smartphones from switching to other search engines.
In April, NHN Corp and Daum Communications Corp said Google's search engine is installed as a default navigation tool and it is impossible for users to switch to other options.
"We will work with the KFTC to address any questions they may have about our business," a Google spokesperson said in a statement emailed to Yonhap News Agency.
The spokesperson denied the allegations.
"Android is an open platform, and carrier and OEM (original equipment manufacturer) partners are free to decide which applications and services to include on their Android phones. We do not require carriers or manufacturers to include Google Search or Google applications on Android-powered devices," the spokesperson said, asking not to be named.