Update 2021-12-07: On Tuesday (07 December), the Norwegian government announced that in places where a minimum distance cannot be kept, masks will generally be compulsory again from Thursday (09 December). The number of visitors to events will be reduced. These measures will initially apply for four weeks.
Update 2021-12-02: As of Friday (03 December), all travellers, both vaccinated and unvaccinated, must take a test within 24 hours of arrival. In Oslo, the use of face masks in crowded places will be mandatory.