The Child Support Agency can use an agreement that has been reached by the parties as the basis for the child support assessment, instead of using the formula calculation. In many cases, parents can make their own arrangements about the amount of financial support they provide for their children, if they can reach agreement. Child Support Agreements can include periodic payments, in-kind payments or lump sum payments.

Agreements can allow parents the freedom to make arrangements to suit their individual needs. However, the object should always be that the children receive a proper level of financial support from their parents, and agreements should not be used to unfairly take advantage of either party.

From 1 July 2008, the legislation has changed to provide for new forms of Child Support Agreements:

Parties should be cautious about the duration of an agreement. The longer the agreement, the less likely it is to be able to anticipate changes in the circumstances of either parent or the child(ren) that may occur in the future. Agreements are inflexible documents that cannot respond to changes in circumstances in the same way that a formula based assessment can.