The Okinawa Prefectural Government is likely to hold a referendum on the construction of a U.S. military base across the prefecture following a deal between ruling and opposition assembly members.

The assembly’s ruling camp, including the Social Democratic Party and the Japanese Communist Party, agreed Thursday with the opposition, including the Liberal Democratic Party, to add a third choice to the two-choice referendum planned for Feb. 24.

The prefectural assembly is likely to approve a required ordinance amendment by a unanimous vote at a plenary session set for Tuesday.

Okinawa Gov. Denny Tamaki welcomed the deal. “Everyone worked very hard,” he told reporters Friday.

The referendum will ask Okinawa voters about the planned relocation of U.S. Marine Corps Air Station Futenma in Ginowan to the Henoko coastal area in Nago.

Five of the prefecture’s 41 cities, towns and villages rejected holding the vote. Following the deal, however, it is highly likely that the referendum will be held in all 41 municipalities.

The five municipalities may hold the referendum later than Feb. 24, depending on progress with preparations. Deputy Gov. Kiichiro Jahana said he expects a delay of one to two weeks.

Others will take the vote on Feb. 24 as scheduled. But they are expected to put off ballot-counting to wait for voting in cities where the referendum will be delayed.

In the referendum, the prefectural government plans to ask whether voters are for or against the base relocation to Henoko, where a new military facility will be built.

The cities of Miyakojima, Ginowan, Okinawa, Ishigaki and Uruma, where conservatives opposing Tamaki have a major presence, refused to take part in the vote.

Some of the five requested the prefectural government increase options in the yes-no referendum. Tamaki responded by urging the prefectural assembly’s ruling camp to consider adding a third option.

The ruling camp, therefore, decided to introduce the option of neither yes or no.

Speaking to reporters after Thursday’s deal, LDP assembly member Moriyuki Teruya, head of the party’s Okinawa chapter, said the five cities will participate in the referendum if the three choices are approved unanimously at the assembly.

Voters in the five cities account for 32 percent of all eligible voters in Okinawa. Without their input, the validity of the referendum is likely to be questioned.

The Okinawa Prefectural Assembly approved a bill to trigger the referendum in October, after a civic group calling for the vote collected about 93,000 signatures and filed a direct petition with the prefecture in September.