Child Support Act 1991, s 5

The child support scheme applies to children and young people under the age of 18, however, an 18-year-old continues to be covered by the scheme if they’re still at school. A child who is covered by the scheme is called a “qualifying child”. To be a qualifying child, a child must also either be a New Zealand citizen or usually be a resident in New Zealand.

Child support isn’t paid for a child if they start living with someone in a marriage, civil union or de facto relationship, or if they become financially independent (which means working more than an average of 30 hours a week, or receiving a benefit or student allowance).

• “Liable parent” – a parent who must pay child support.
• “Receiving carer” – a parent that receives payment (they used to be called the “eligible custodian”).
• “Qualifying child” – a child who can be covered by the child support scheme. They must be under 18, and they must not be financially independent or living with someone in a marriage, civil union or de facto relationship. However, an 18-year-old will continue to qualify if they’re still at school.
• “Dependent child” – This means a child you have with your current partner and who isn’t covered by child support.
• “Income percentage” – A parent’s income percentage means their income as a proportion of the combined income of the two parents. For example, if your children’s other parent earns one and a half times your income, your “income percentage” is 40% and theirs is 60%. In assessing whether you’ll pay or receive child support, Inland Revenue weighs your income percentage against your “care cost percentage” (see below).
• “Care cost percentage” – Your care cost percentage is the share of the total costs of raising your children that the child support scheme sees you as already meeting by providing ongoing daily care for them. In assessing whether you’ll pay or receive child support, Inland Revenue weighs your care cost percentage against your “income percentage” (see above).
• “CS percentage” (Child Support percentage) – This is the difference between your “income percentage” and your “care cost percentage” (see above). If your income percentage is less than your care cost percentage, this means your share of the costs of raising the children is more than met by the ongoing daily care you’re providing for them, and so you’ll be paid child support by the other parent. If the figure is positive, you’ll have to pay child support to the other parent.