SEOUL—South Korea denied a request by Alphabet Inc.’s Google to export digital-map data from the country, effectively blocking the U.S. technology giant from expanding its limited local-map services there.

For eight years, Google has sought approval to store South Korean map data on its foreign servers, a step it says is necessary to provide a full range of mapping services, including 3-D maps and traffic updates. South Korea is a global outlier in having only basic Google map services even after they were officially launched there in 2008.

Seoul has in the past refused the requests because, it says, the export of map data could compromise the country’s security against North Korea by exposing information about its military and other facilities.

On Friday, South Korea’s Ministry of Land, Infrastructure and Transport, which oversees the country’s map-related policies, reiterated those concerns, saying the government denied Google’s request to export data because it could aggravate security issues with North Korea. The decision was passed unanimously by eight government entities, including the country’s foreign-affairs ministry, trade ministry and national intelligence division.

The ministry also said Google hadn’t accepted the government’s suggestion of addressing the security concerns by making changes to satellite images available through its mapping service. The government said it is open to reconsidering the Mountain View, Calif., company’s request if it changes its position.