The Okinawa Prefectural Government on Monday filed a fresh lawsuit against the central government over the planned relocation of the Futenma base.
This suit is against a dispute settlement panel's decision favoring the central government's effort to continue working on a landfill project to host the planned replacement base.
The prefecture and the central government have already each filed a lawsuit against the other over the plan to move U.S. Marine Corps Air Station Futenma from a crowded residential district in Ginowan to the less-populated Henoko coastal area of Nago, also in Okinawa.
The fresh suit was filed at the Naha branch of the Fukuoka High Court.
The feud deepened after Gov. Takeshi Onaga revoked in October his predecessor's permission for the landfill work to transfer the base, prompting the land minister to suspend the validity of Onaga's revocation the same month.
Onaga then filed a complaint with the third-party dispute settlement panel on the minister's action, but the panel decided to reject the complaint, saying the case was not suitable for review by the panel.
Wednesday was the deadline for filing a suit regarding the panel's decision.
The central government has been seeking to relocate the base within the prefecture as Japan and the United States struck an accord in 1996 on the return of the land being used by the Futenma base to Japanese control, but progress has been slow amid strong local opposition.
Onaga and many residents of Okinawa want the base moved outside the prefecture to reduce the burden from hosting the bulk of U.S. forces in Japan.