Japan's Defense Ministry is making arrangements to extend the planned completion date for the relocation of a US military base within Okinawa Prefecture.
The central government wants to relocate the US Marine Corps Futenma Air Station in Ginowan City to the less populated Henoko district in Nago City.
Under the plan agreed to between Japan and the United States in 2013, the relocation work should take five years. But the ministry is now considering extending it to roughly 10 years.
The start of the landfill work was delayed due to opposition from Okinawa Prefecture and began in December last year.
Soft ground makes up about 40 percent of the seabed of the planned relocation site.
The Defense Ministry is considering reviewing the construction schedule in order to carry out reinforcement work.
The plan agreed to in 2013 targeted fiscal 2022 for the return of the Futenma base site to Japan. But if the timetable is revised that would be pushed back to the 2030s.
Construction work may take even longer. The prefectural government is demanding that land reclamation be stopped immediately and is expected to reject the central government's revised plan.