Seoul argues that if it allows the government-supplied map data to leave the country, the locations of its military facilities and other sensitive sites could be revealed.
Seoul rejected Google's request to export government-supplied data for its global mapping service on Friday, arguing that such a move would make South Korea vulnerable to any possible attack by North Korea.
South Korea is concerned that its national security is under threat as North Korea has conducted several nuclear tests in recent years. The 1950-53 Korean conflict ended with a ceasefire rather than a peace treaty and therefore the two nations are conscientious of each other's actions.
"There are concerns that Google's request to export map data could escalate security threats amid confrontation between South and North Korea," the land and transport ministry said in a statement.
South Korea's National Security law prevents Google from exporting government-supplied maps on the grounds that it could reveal the locations of military facilities and other sensitive sites.
Google says the law is outdated and unfairly restricts the company from providing a full range of mapping services such as driving directions, public transit information and satellite maps. For the last eight years, it has sought approval to store the data on its foreign servers.
Google spokesperson Taj Meadows said, "We are disappointed by this decision. We've always taken security concerns very seriously," but added that the company remains hopeful it will be able to provide South Koreans with the full suite of Google Maps services in the future.