central organization; central authority
Refers to a body that holds central authority or coordinates activities across a network, such as a headquarters, central committee, or umbrella organization.
The central organization for this project is in Tokyo.
Each branch operates according to the instructions of the central authority.
central government agency
Specifically a government body at the national level, such as a ministry or agency, as opposed to local government offices.
A notice from the central government agency was sent to each prefecture.