Industrial giant Hitachi has decided to allow employees in Japan to work without a face mask on, with the proviso that they carry out basic anti-infection measures.

In the spring of 2020, Hitachi recommended that more than 150,000 employees, including those at domestic group firms, wear a mask as part of its coronavirus-prevention protocol.

The change in policy is in part aimed at preventing heatstroke as summer approaches. New government recommendations on masks also helped to prompt the shift.

Hitachi now says employees need not wear a mask indoors or outside if they are not engaged in conversation and can maintain a distance of more than 2 meters from others.

At the firm's head office in central Tokyo, employees were seen on Friday working without a face mask.

The company is still calling on workers to wear a mask when they speak with others indoors in close proximity. It also says it will continue to carry out antivirus measures, including ventilation of indoor spaces and checking the body temperature of those entering its facilities.

A senior official says some employees reported that the new guidelines would be a useful prompt encouraging people to think about when a mask should be worn and when a face covering can be dispensed with.