TOKYO, Feb. 1 (Xinhua) -- A referendum on the central government's controversial plans to relocate a U.S. airbase within Japan's southernmost prefecture of Okinawa will be held across the entire prefecture later this month, Okinawa authorities said Friday.

The vote on the contentious relocation of the U.S. Marine Corps Air Station Futenma from the crowded residential area of Ginowan to the coastal, less populated region of Henoko, also in Okinawa, will now cover all eligible voters in the prefecture, as three cities that were opposed to the vote have reversed their decision.

Owing to the prefectural assembly on Tuesday passing a bill to expand the referendum's voting conditions from a simple "yes" or "no" vote on the base's relocation to include a third "neither" option, the city mayors who had been opposed to the referendum on the grounds that the format would not cater to all residents' opinions, consented to go ahead with the vote.

A prior sticking point for some of the city's mayors had also been the budget associated with holding the referendum, which in some cases had been previously rejected by local assemblies.

"Our city will cooperate with the prefecture to hold the referendum," Ishigaki Mayor Yoshitaka Nakayama was quoted by local media.

His remarks came after the city's assembly on Friday adopted the budget for the voting to go ahead.

Ginowan Mayor Masanori Matsugawa, meanwhile, told a press briefing on the matter that his city will now go ahead with the vote as the addition of a third option for voters in the referendum was a proviso that was highly valued by his city.

The referendum, to be held on Feb. 24, while not being legally binding, will, as Okinawa Governor Denny Tamaki hopes, show the true extent to which the people of Okinawa are staunchly opposed to the central government's plans to relocate the air base.