A shop has begun using Robovie to identify and ask customers to cover up as the country risks a third wave of coronavirus infections.
The laser-guided bot developed by the Advanced Telecommunications Research Institute International in Kyoto can also step in if shoppers fail to socially distance while queuing up to pay.
The trial began last week at the club shop of Cerezo Osaka, a professional football team, and will run until at least the end of the month.
Robovie’s developers, who are behind a host of robotic innovations, hope the experiment will reduce close contact between shoppers and staff.
They added that they believe most people will feel less embarrassed by being asked to cover up by a robot than by a fellow human being.
Robovie comes equipped with pre-loaded information about the shop’s layout.
It uses a camera and sensors to observe people’s movements, and lasers to measure the distance between them, according to the Kyodo news agency.
Social distancing and mask wearing is generally accepted in Japan and Robovie can also guide customers around the shop.
Japan has avoided the large number of cases and deaths seen in some other countries.
But a recent rise in daily Covid-19 infections has led to calls for new measures to prevent hospitals from being overrun as winter approaches.
It reported 1,441 new cases on Sunday, slightly down on the record 1,737 infections recorded the previous day, with Tokyo, Osaka and other cities and regions reporting record daily rises over the weekend.
The country has confirmed 119,420 cases and 1,908 deaths since the start of the pandemic, according to public broadcaster NHK.
The prime minister, Yoshihide Suga, has said there are no plans to rethink a subsidised domestic tourism campaign or to declare a second state of emergency.