About 20 central and local government officials have attended the political school established by Osaka Mayor Toru Hashimoto.
So far, about 880 participants have attended events at Ishin Seiji Juku (Political Restoration School), including officials from the Finance Ministry, the land ministry and the Nuclear and Industrial Safety Agency, sources said.
Municipal officials from outside Osaka also have attended the school's lectures and discussion sessions with academics and other guests, they added.
Critics are accusing Hashimoto of having a double standard for curbing the political activities of Osaka employees while allowing other public servants to take part in Ishin Seiji Juku.
In July, Osaka's municipal assembly passed an ordinance submitted by Hashimoto that in principle allows the mayor to take disciplinary action against municipal workers if they engage in any political activities.
Hashimoto's Osaka Ishin no Kai (One Osaka) party launched the political school to groom future leaders able to reform traditional bureaucratic structures. Some of those trained at the facility are scheduled to take to the streets and deliver stump speeches in mid-September.