South Korean antitrust regulators have raided the Seoul office of Google as part of an ongoing probe into alleged unfair trade mobile search engine market by the search giant.

The on-site investigation resulted from complaints filed by two local internet search companies, Naver and Daum Communication, in April this year.

In their complainant, asked the Korea Fair Trade Commission (KFTC) to probe Google over claims it restricts local mobile service providers and smartphone manufacturers that have adopted its Android operating system from pre-loading rival services.

However, the company refuted this claim in its latest statement: "We do not require carriers or manufacturers to include Google Search or Google applications on Android-powered devices."

"We will work with the KFTC to address any questions they may have about our business," a Google spokesperson in a statement

Google is facing similar antitrust investigations and proceedings in the US, Europe and several other Asian countries.