Osaka and its surrounding prefectures have asked Japan's national government to expand a state of emergency to the western cities in an effort to contain the latest COVID-19 outbreak.
Concerns across the country remain high as, despite a new lockdown, daily infections in the capital Tokyo stayed above 2,000 on Saturday.
Yasutoshi Nishimura, the country's economy minister, told media the situation in the western cities of Osaka, Kyoto and Hyogo was severe and the declaration of a wider state of emergency was being considered after a request from the cities' governors.
Japan declared a limited state of emergency in Tokyo and three prefectures neighbouring the capital on Thursday to stem a surge in infections, resisting calls from some medics for wider curbs due to the economic damage they would cause.
Tokyo reported 2,268 new daily coronavirus cases on Saturday, according to the public broadcaster NHK, the third straight day the city has registered more than 2,000.