https://helsenorge.no/coronavirus/fo...lers-to-norway
For stays shorter than 10 days, you still need to provide documentation for the days you are staying in Norway.
So yes you can enter for less than 10 days, but you won't be there for a day so you can just explain at the border if questioned... But last week the e-gates were open and I didn't speak to anyone. However, the assumption is you are an EU/EEA citizen/resident (if you are non-EU/EEA citizen/resident then please disregard my post, I do not believe you can enter)