The Nuclear Regulation Authority (NRA) filed the appeal at the Osaka high court. Kansai Electric said in a statement it would strive to show that the plants are safe to operate to get the appealed overturned.
Earlier this month the Osaka court ruled in favour of about 130 plaintiffs who said that the two units in Fukui prefecture were vulnerable to major earthquakes.
Ohi-3 and -4 are both 1,127-MW pressurised water reactor units. Ohi-3 began commercial operation in 1991 and Ohi-4 in 1993.
The two plants have been offline for scheduled maintenance since earlier this year.