Japan's land minister will approve on Thursday ground improvement work as part of a project to relocate a US military base in Okinawa Prefecture.

Saito Tetsuo made the decision after Okinawa Prefectural Governor Tamaki Denny decided to defy a high court ruling that orders the prefecture to approve the work at an offshore site in Henoko, Nago City, also in Okinawa.

Despite opposition of the Okinawa government, the central government plans to relocate the US Marine Corps Futenma Air Station to an offshore site from a densely populated area in Ginowan City.

But the seabed at the planned reclamation site was found to be too soft.

The central government sought permission from the prefecture to revise its plan and carry out work to reinforce the seabed. Okinawa has not approved the revisions, and the work remains stalled.

Land minister Saito will give the green light to the planned work on Thursday in place of the prefectural government.

In light of Saito's decision, the Defense Ministry is making arrangements to start ground improvement work in Oura Bay in mid-January.

Officials have already begun procedures for the work, signing contracts with construction companies. Work to build embankments is to start after material and equipment are brought to the construction site.

It is the first time that the central government has overruled a decision by local authorities based on the local autonomy law.

Okinawa's governor is calling for a halt to the work and is seeking dialogue with the central government. The central government's decision to proceed with the work is expected to draw sharp reaction from the people of Okinawa.