Official campaigning began on Thursday in Okinawa for a prefectural referendum on landfill work to relocate a US base within the southern Japanese prefecture.
The referendum on the landfill work in a coastal area of Henoko will be held on February 24.
The reclamation is part of the work to build a replacement facility for the US Marine Corps Futenma air station, which is located in a crowded residential area of Ginowan City.
Voters will choose from three options listed on the ballot paper asking what they think of the landfill for the base relocation -- "yes," "no," or "neither." The result will not be legally binding.
But an ordinance on the referendum stipulates that the Okinawa governor must respect the outcome, if a quarter of eligible voters support the option that wins the most votes. It also says the governor must notify the Japanese prime minister and the US president of the result.
Japan's central government began pouring soil into the sea for the new base in December last year, despite strong opposition from the Okinawa prefectural government.
The base relocation plan is based on a 1996 agreement between Japan and the United States.