Is parental benefit the same as child maintenance?

No.

Parental benefits are a payment that parents receive from Barsilsskipanin so that they can leave their work to stay at home with their child during the first period of the child's life. This website deals with that.

Child maintenance, on the other hand, is the payment that one parent makes to the other to help with the everyday costs of a child if the parents do not live together. Almannaverkið administers this. See the link to their website under quick links.