All assembly members of Hyogo Prefecture, western Japan, are now set to call on the governor to resign.
Prefectural governor Saito Motohiko has been facing allegations of power harassment and other misconduct.
In March, the then-chief of the prefecture’s Nishi-Harima bureau released a document on cases of alleged harassment committed by Saito.
The then-chief was reprimanded after an internal investigation concluded a core part of the document was false.
The matter sparked a controversy over whether the disciplined official should have been protected as a whistleblower for the sake of the public interest by law.
The prefectural assembly set up a special committee to look into the case.
The former bureau chief was found dead in July just before he was scheduled to be summoned for questioning at the committee. Police think he committed suicide.
Then the committee conducted a survey covering all prefectural employees.
The interim results on the survey found that nearly 40 percent of the respondents said they had seen or heard of alleged abuse of power by the governor.
Members of the largest voting group in the assembly, the Liberal Democratic Party, and three other voting groups as well as independents plan to urge the governor on Thursday to step down.
The move comes after Japan Innovation Party members, who make up for the second largest voting group, called for his resignation.
If the governor rejects the demand, the LDP members are considering submitting a no-confidence motion against him on September 19, the first day of a regular prefectural assembly meeting.
At a news conference on Wednesday, Governor Saito reiterated his intention not to resign.
Saito admitted he is facing a severe situation. But he noted that in the election three years ago, he was given a mandate by voters to do his best for a four-year term. He said, therefore, he is determined to follow through with his term.
If a no-confidence motion is adopted, the governor is required to choose whether to dissolve the prefectural assembly or to lose his position.
Saito said he will decide how to respond in line with the options provided by law.