Prime Minister Shinzo Abe's ambition to restart the country's fleet of nuclear reactors may face further challenges from regional elections.

The victory of an anti-nuclear gubernatorial candidate in Niigata on Sunday, following a similar win in Kagoshima earlier this year, is complicating the efforts of the ruling Liberal Democratic Party to revive Japan's reactors. There will be at least three such elections next year in areas where utilities are vying to restart reactors.

"Even as the Abe administration remains committed to including nuclear power as part of Japan's energy mix, implementing this vision will require overcoming ever-more-dogged resistance from local communities and their representatives," Tobias Harris, a vice president with Teneo Intelligence in the District of Columbia, said in a note Monday. "The restart process will continue to proceed unevenly at best."