The governor of Japan's southwestern prefecture of Okinawa has said he will consider a response to a Supreme Court ruling against the prefectural government's objection to a land reclamation project to facilitate the relocation of a US military facility within Okinawa.

The top court on Monday turned down Okinawa's appeal of a high court decision upholding the central government's directive demanding the prefecture approve a proposed change to the reclamation plan.

Following the court decision, Okinawa Governor Tamaki Denny told reporters that it is extremely regrettable because he had hoped for a fair and neutral ruling based on the principle of local autonomy.

He also said he is deeply concerned that the ruling may undermine the autonomy and self-reliance of municipalities and also the principle of local autonomy stipulated in the Constitution. He noted that the prefecture will compose its response after studying the ruling.

The local government will now be obliged to give its approval to the work in the Henoko district of Nago City.

If the governor does so, that could shake his base of support and affect his management of the local government as he has consistently opposed the relocation of the US airfield to Henoko from Ginowan City, also in the prefecture.

If Tamaki refuses to issue the approval, the central government will be allowed to start a procedure known as execution by proxy, and approve the design revision in place of the prefecture.