The recommendation applies in Oslo as well as the Indre Østfold municipality, news agency NTB reported Friday.
Minister of Health Bent Høie, announcing the measure at a press briefing Friday afternoon, stressed that face masks do not replace social distancing and hygiene recommendations.
Health authorities in Norway recommend a social distance of at least one metre.
“The protective effect of face masks is estimated to be 40 percent, while keeping a distance of at least one is estimated to reduce the risk of infection by 80 percent. The metre is therefore more important than the face mask,” Høie said.
The recommendation could be extended beyond rush-hour public transport, should Norway continue to see an increase in infection, according to a Norwegian Institute for Public Health (NIPH) assessment.
If municipalities or specific areas experience high infection rates, face masks will be recommended for use in shops, at universities, at museums and on the street, newspaper VG reports.
The NIPH face mask recommendation applies primarily to situations in which it may not be possible to maintain a distance of one metre, the health authority writes in a statement.
Using face masks is a sign of community solidarity, Høie suggest at Friday’s briefing.
“Many think that you use a face mask to protect yourself against infection. But you are first and foremost protecting others from infection if you have the virus without knowing it,” he said.
Norwegian authorities will follow Friday’s announcement with an information campaign on correct use of the protective item.
Children up to seventh grade will not be advised to use face masks while children under two years old should not use them at all.
The Norwegian health authority recommendation comes into effect from Monday August 17th and will be in place for an initial two weeks.