The regulations concerning entry to and residence in Svalbard are different from the regulations on the Norwegian mainland. Although the Norwegian mainland is part of the Schengen area, Svalbard is not, and due to this fact, an ID control is required of all visitors visiting Svalbard.

Passports or national identity cards will satisfy Schengen regulatory requirements for identity verification. Since national ID cards are unavailable in Norway, Norwegians can identify themselves with a driver's license issued after 1998, credit cards or Ministry of Defence Identity Card. This is a transitional arrangement that applies until a national ID card is introduced in Norway. The documents must be issued in Norway and at least contain the traveller’s name, photo and date of birth. Persons under 18 years will in many cases be unable to have such documents issued. Norwegian children can therefore be identified by an adult accompanying the child to the plane or travelling with the child. After national ID cards are introduced, Norwegians (including children) must identify themselves with a passport or national ID card.

You can read more about the rules and regulations for passport and visa here:
http://www.sysselmannen.no/en/Visitors/Entry-and-residence/ 

https://www.regjeringen.no/en/aktuelt/new-rules-for-travellers-between-svalbar/id628539/