Defense Minister Gen Nakatani said Tuesday an offshore boring survey at the proposed new site for the U.S. Marine Corps Air Station Futenma will continue until June, rather than winding up by the end of March as planned.

"We will wrap up the survey by June and begin the process of landfill work in summer at the earliest," Nakatani told a news conference.

The offshore landfill is needed to create two runways for the planned base, which is to be built in the Henoko district of Nago, Okinawa Prefecture.