The government plans to start maritime construction work as early as next week at the planned relocation site for a key U.S. airbase in Okinawa, a government source said Tuesday.

The move, which is likely to trigger further local opposition, comes after the government's resumption in late December of land construction work at U.S. Marines Corps Camp Schwab located adjacent to the relocation site.

The maritime work is part of the central government's plan to relocate the operations of U.S. Marine Corps Air Station Futenma from densely populated Ginowan to the Henoko coastal area in Nago, farther north on Okinawa Island.