Tokyo, Osaka and Yokohama are emerging as likely candidates for casino resorts under the government's new bidding framework, triggering criticism from smaller cities that say it undermines Prime Minister Shinzo Abe's goal of reviving rural areas.

Most global casino operators have indicated an interest in building resorts only in any of the three cities, given their relatively high population and proximity to major international airports. To be selected, operators and municipalities will have to team up and submit a concrete proposal to the government, according to guidelines published this month.

"The guidelines have changed the power structure between operators and local governments," Wakayama Gov. Yoshinobu Nisaka said at a news conference at the Japan Gaming Congress on May 11. "Where did the view that this was for local revitalization go?"