The Kanagawa Prefectural Government will refuse to accept resident registry data from the city of Yokohama because of its policy of allowing citizens to opt out of the system, prefectural government sources said Saturday.

The move would exclude the nation's largest municipality from the resident registry network. Launched Aug. 5, the network allows different levels of government to share citizens' personal data.

The prefectural government has to refuse the data because the Basic Resident Registration Law makes no exception for Yokohama's policy, one official said.

The Ministry of Public Management, Home Affairs, Posts and Telecommunications has argued that Yokohama's optional participation is illegal.