Notifying the Norwegian Population Register about your move
You must notify the Norwegian Population Register (and through them, the Norwegian Tax Office) when you move from or return to Norway (and when you move around in Norway, too). Norsk versjon - Melde innflytting til folkeregisteret.
Remember that when you return from abroad you cannot notify the different government agencies of your return via the Internet. You must submit a written notification in person. Your local tax office can also help you with information about this, along with details of about your taxes and tax card.