Protesters holding signs reading "No new Henoko base" rally near a gate of Camp Schwab, a US Marine Corps camp, in the Henoko neighborhood of Nago, northeast of Okinawa, Japan, Dec 20, 2023. (PHOTO / KYODO NEWS VIA AP)

TOKYO - The Japanese government on Thursday gave the green light to a revised plan for a key US base relocation within Okinawa prefecture, taking the unprecedented step of overriding the prefectural government's objection, local media reported.

The Defense Ministry will start to work to reinforce soft ground at the relocation site for the US Marine Corps' Futenma air base as early as Jan 12, Kyodo News reported, citing a government source.

The approval of the design change marked the central government's first-ever proxy execution of a local government administrative task under the local autonomy law, the report said.

READ MORE: Okinawa rejects court order over revised US base transfer plan

The proxy execution came after Okinawa Governor Denny Tamaki, who has been pushing to move the Futenma base out of the southernmost prefecture, refused to follow a recent court order for him to approve the design change.

More than 70 percent of local residents opposed the US military base construction on the Henoko landfill, according to the 2019 Okinawa prefecture voting results

The central government plans to relocate the Futenma base from a crowded residential district in Ginowan to the less populated Henoko coastal area in Nago, which is also in Okinawa.

"It is not just an issue for Okinawa prefecture," Tamaki told reporters following the central government's approval, noting that the execution by proxy is unacceptable as it robs the prefectural government's administrative authority and means they are trying to construct a new base by infringing on "our autonomy and independence".

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In September, Tamaki told a United Nations Human Rights Council meeting in Geneva that the concentration of US military bases in Okinawa threatens peace, noting that the Japanese government is forcibly filling in precious sea areas to build a new US military base, regardless of the opinions of local residents.

The governor has also, on multiple occasions, expressed concerns over excessive levels of toxic per- and poly-fluoroalkyl substances detected in the water around US military bases in Japan.

READ MORE: Japan's Okinawa governor says US military base threatens peace

The island of Okinawa hosts 70 percent of all the US military bases in Japan while accounting for only 0.6 percent of the country's total land area. More than 70 percent of local residents opposed the US military base construction on the Henoko landfill, according to the 2019 Okinawa prefecture voting results.