Tokyo, Jan 11 (IANS): The Japanese government has begun ground improvement work for the relocation of a key US military base within Okinawa prefecture after overriding the local government's objection, regardless of the opinions of local residents.

Chief Cabinet Secretary Yoshimasa Hayashi told a press conference on Wednesday that the commencement marks the start of work, likely to take more than nine years, to reinforce the undersea soft ground at the relocation site for US Marine Corps' Futenma air base.

The ground improvement is necessary to carry out landfill work that is part of the project to relocate the Futenma base from a crowded residential district in Ginowan to the less populated Henoko coastal area of Nago, which is also in Okinawa.

Okinawa Governor Denny Tamaki told reporters on Wednesday that this is something the government is doing for its own convenience, and it is extremely regrettable, Xinhua news agency reported.

On December 28, 2023, the Japanese government gave the green light to the plan on behalf of the Okinawa government, taking an unprecedented step of overriding the prefectural government's objection.

The approval marked the Central government's first-ever proxy execution of a local government administrative task under the local autonomy law, according to media reports.

Okinawa, which hosts 70 per cent of all the US military bases in Japan, has long opposed the base transfer within the southern island prefecture, seeking instead to move the base out of the prefecture altogether.

In September 2023, 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 the new US military base.