South Korea\'s top two Internet companies filed complaints with the antitrust watchdog Friday over Google\'s alleged practice of stifling competition in the local mobile phone search market. Daum and NHN Corp told the Korea Fair Trade Commission (KFTC) that Google exploited its position as developer of the Android mobile operating system to have its search function preloaded on local smartphones. They said this limited access by local search engines to smartphones using the Android operating system. \"Through a marketing partnership with major smartphone producers, Google has prohibited other market players from pre-installing their search window or related applications,\" NHN said in a statement. NHN\'s Naver has a market share of around 56 percent of the domestic mobile search market while Daum had around 16 percent as of last month, NHN said, citing market research data. \"Google\'s market share in the local internet search market only accounts for around 2 percent but due to such an unfair act, its share in the mobile market is fast rising in Korea, and it stands at around 15 percent,\" a NHN spokesman said. Google denied the accusations, asserting that it has never pressed device manufacturers or mobile operators to use its mobile platform. \"Android is an open platform, and carrier partners are free to decide which applications and services to include on their Android phones,\" it said in a statement. It said Google regularly enters into business agreements where carriers can choose to pre-install Google mobile services including a search function. \"But we absolutely do not require carriers or manufacturers to include Google Search on Android-powered devices. We look forward to working with the KFTC to address any questions they may have.\" Android smartphones sold in South Korea provide the Google search engine as a default. South Korean search portals complain that this makes it inconvenient for phone owners to switch to a different search window.