I don't think what was written above for non EU applying for permanent residence is entirely correct.
The best way to check for the eligibility of permanent residency is to check UDI.
https://www.udi.no/en/want-to-apply/per … residence/
I only know about my case and I am from Singapore. As far as I understand , as long as I stays for 3 years in Norway under a valid residence permit (eg. skilled worker permit, family unification), I am eligible to apply for permanent residence.
BUT I need to fulfill requirements such as
1. You must have stayed in Norway for the past three years and have held residence permits that form the basis for a permanent residence permit.
2. You must have held valid permits throughout the three-year period and still hold one when you apply for a permanent residence permit.
3.You must have resided in Norway continuously for the past three years.
4. You cannot have been convicted of a criminal offence or been ordered to undergo enforced psychiatric treatment or care (applies if you are over the age of 15).
If you have been convicted of a criminal offence, your application may be rejected and a longer residence period may be required. If you are charged with or put under investigation for a criminal offence during the application period, we will suspend the processing of your application. Once the criminal case has been decided, you must yourself contact your local police district and request that we resume the processing of your application.
5.You must normally have completed mandatory tuition in the Norwegian language and social studies and pass the concluding tests, or document that you have been granted exemptions by the municipality (applies if you are between the ages of 16 and 55).
Persons who can be exempted from one of more of the requirements
Spouses and cohabitants of Norwegian citizens who are employed by a Norwegian embassy or consulate are exempt from the requirement for three years' residence in Norway and from the requirement for tuition in the Norwegian language.
6.Persons who do not meet the condition for three years' residence in Norway can, in some cases, be granted permanent residence if, during the past year, they have held a residence permit that forms the basis for a permanent residence permit, and
they have stayed in Norway for a long time (eight to ten years) holding residence permits, or
they have lived for a long time on Svalbard, or
there are particularly strong grounds of reasonableness.