Defense Minister Gen Nakatani said the government will extend by three months an offshore boring survey now under way at the replacement site for the Futenma military base in Okinawa Prefecture.
Landfill work for the new air base in Nago will begin this summer as scheduled even though the boring survey will now run until the end of September, Nakatani said Tuesday at a news conference.
It is the third extension since the government began surveying the seabed off the Henoko coastal area last August to assess geological conditions and the foundation for the relocation site.
The extension was made necessary because the government has not finished its survey at five of 19 undersea locations, according to the Defense Ministry. Rough weather is one reason for the slow work.
The findings are to be reflected in the design for the replacement facility.
Japan and the United States have agreed to relocate the Futenma base from the city of Ginowan to the less populated Henoko coastal area in Nago.
However, opposition to building the replacement base within Okinawa has generated fierce local opposition and Gov. Takeshi Onaga has pledged to stop the new base from being built.