All persons who, pursuant to Norwegian regulations, are resident in Norway are liable to pay tax on all their income and wealth. You become resident for tax purposes if you live in Norway for more than 183 days during a 12-month period or more than 270 days during a 36-month period.
A person who is not resident in Norway long enough to be considered resident pursuant to the Norwegian tax regulations is still liable to pay tax on, among other things, income from employment and income from business in Norway.
The obligation to pay taxes in Norway may be limited by a tax treaty between Norway and your home country. It is worth noting, however, that if you work in Norway for a Norwegian employer or if you are on hire to a Norwegian employer, you are always liable to pay tax in Norway.