Technically, yes, they have force until the child turns 18, but it's more likely than anything else that any action on this front (contravention application, initiating application, etc) would result in the court making orders reflective of what the child wants. Under s 60CC of the Family Law Act 1975, views expressed by the child are given weight when considering what's in their best interests, and the general consensus is the older they are, the more weight their views are given. By 16, the orders would likely be that the child live with the father and spend time with the mother in accordance with the child's wishes. Hope this helps.