The Children Act regulates the establishment of and changes to paternity.

Married parents

If the parents are married, the man to whom the mother is married is regarded as the child's father. This is called the pater est rule. If the child is born while the mother is formally separated, the paternity is established as if the parents are not married.

Unmarried parents

When the child's parents are not married to each other, the paternity does not follow automatically. Usually, paternity is established in these cases by the mother stating the name of the father and he acknowledging paternity. The father can acknowledge paternity in the presence of a midwife or a doctor at a pregnancy checkup or in connection with the birth. Paternity can also be acknowledged in writing by personal attendance at the Labour and Welfare Administration (NAV) office or the tax office or in the presence of a judge. Paternity may also be established by a judgment. In such cases, the judge usually orders a DNA test of the man whom the mother has stated to be the father.

Acknowledging paternity abroad (Norwegian law)

When the parties are related to Norway, paternity may be acknowledged at a Norwegian diplomatic or consular official in a foreign country. In cases where the parties are more closely related to another country, the paternity shall usually be determined there.

Acknowledging paternity abroad (foreign law)

Paternity that follows directly from foreign legislation is usually recognised in Norway. This mainly applies to paternity that follows from the pater est rule in other countries.

Other paternity may be acknowledged in each case by the Labour and Welfare Administration (NAV) International in order to be valid in Norway.

The Labour and Welfare Administration (NAV) is responsible for ensuring that the paternity of children born in Norway is established.