The fine stems from a pair of celebrations linked to Solberg's 60th birthday at the end of February, for which she gathered family members at a ski resort in Geilo, in central Norway.
Police cited two incidents: one at a restaurant and one where the group gathered for sushi in a rented home. Solberg was not present at the restaurant due to an eye problem.
In each case, about 13-14 people gathered. But rules in place at the time to prevent the spread of the coronavirus limited such gatherings to 10 people.
Solberg had already apologized for the incidents, after they first came to light.
"I should have known better," she told the broadcaster NRK at the time.
"Someone like me, who tells other people every day about infection protection should have known the rules better."
The comments prompted the police investigation.