This article was written by Melinda Gao Pricipal Solicitor and Simone Garcia Solicitor at W & G Lawyers.
In family law practice, few topics carry as much quiet resentment as child support. After enough of these conversations, the pattern is almost universal: one party thinks it is not enough, and the other party thinks they are paying too much. The remarkable thing is that both are usually sincere. The paying parent looks at the monthly transfer and feels stretched; the receiving parent looks at the school fees, the orthodontist’s quote and the swimming lessons and sees a number that does not come close.
There is another way to set that number — one the parents design themselves. This article explains how the government assessment works, when a child support agreement is worth considering, what the law requires before an agreement truly binds, and how an agreement fits into the government system.
Where the government’s number comes from
Child support is federal law, administered by Services Australia under the Child Support (Assessment) Act 1989 (Cth), so the rules are the same across the country. Unless the parents agree otherwise, the amount payable is set by an administrative assessment: a statutory formula built on both parents’ taxable incomes, the number and ages of the children, and the care percentage — worked out from the nights the children spend with each parent across the year.
Two things about that formula matter in practice. First, the parenting schedule is the biggest single driver of the figure — which is why child support should be thought through before parenting arrangements are agreed, not after. Second, the formula is fair but generic. It does not know that your child attends a private school, needs braces next year, or plays representative sport. And because the assessment moves with each parent’s income, the figure can change year to year — unsettling for anyone trying to plan a child’s future.
When an agreement is worth considering
A child support agreement lets parents replace or top up the formula with terms shaped to their own child. In our experience, agreements earn their keep where:
- The child has expenses the formula ignores — private school fees, health insurance, orthodontics, therapy, extracurricular activities. An agreement can say exactly who pays for what, and how.
- Both parents want certainty — a settled arrangement for years ahead, instead of an annual recalculation and an annual argument.
- Income is complicated — self-employment, business structures, trusts or overseas income can make the formula’s result feel wrong to everyone. A negotiated figure both parents accept can be closer to fair than an assessment neither trusts.
- Child support is part of a bigger settlement — parenting consent orders, a property settlement and a child support agreement can be finalised together as one package, including lump sum or property-based arrangements in place of some or all periodic payments.
- The parents want to stay collaborators — a signed agreement is itself a statement: we have separated, but on our children we still work together.
Limited or binding?
The law offers two kinds of agreement, and they are very different instruments:
| | Limited agreement | Binding agreement |
| Independent legal advice | Not required | Required for each parent, certified by their own solicitor, before signing |
| Amount | Must be at least the assessed rate | Any amount the parents agree — above or below the formula |
| Getting out | Either parent may end it after three years, or earlier if the notional assessment changes by more than 15% | Cannot be varied. Ends only by a new agreement, a formal termination agreement, or a court setting it aside — broadly, only in exceptional circumstances |
| Best suited to | Shorter-term or trial arrangements | Long-term certainty — school fees, insurance, settled amounts to adulthood |
What makes a binding agreement binding
The Act’s language here is unusually absolute: an agreement is binding if, and only if it is in writing and signed, and each parent received independent legal advice — from their own solicitor, before signing — about the effect of the agreement on their rights and its advantages and disadvantages, with each solicitor’s signed certificate annexed to the agreement. Without those certificates, the document is simply not a binding child support agreement, however willingly it was signed.
Parliament set the bar that high for a reason. Once a binding agreement is made, it cannot be amended — not even by consent. If circumstances change, the parents need a whole new agreement (with fresh legal advice on both sides) or a court order, and courts will only set a binding agreement aside on narrow grounds. A binding agreement may need to work for a decade or more, so it has to be drafted for the future, not just for today: What if the care arrangement changes? What if a parent’s income collapses? What if the child changes schools, or needs major medical treatment? Should the amounts be indexed so they keep pace with real costs? In the agreements we are asked to review, the problems are rarely in what was written — they are in what was left out.
How an agreement fits into the government system
Signing an agreement does not mean leaving the Services Australia system — the two run side by side, and the joins are where families most often get caught:
- The agreement becomes the official liability. Once accepted by the Registrar, the agreement replaces or modifies the administrative assessment.
- Family Tax Benefit is not based on the agreement amount. Services Australia still calculates a “notional assessment” — what the formula would have produced — and FTB Part A is worked out on that, not on what the agreement says. A generous package does not reduce your FTB; it does not lift it either. This needs to be modelled before signing, together with how the collection method affects FTB.
- How the money moves is still a separate choice. Parents can transfer payments privately (Private Collect) or have Services Australia collect and pass them on (Child Support Collect). Agency collection turns unpaid amounts into a debt to the Commonwealth and unlocks real enforcement powers — deduction from wages, interception of tax refunds, even orders stopping a persistent non-payer leaving Australia. Under Private Collect, none of that exists until you switch or go to court — and the agency can generally only backdate collection of unpaid amounts by about three months. Waiting to see whether payments resume can quietly cost you the right to recover them.
- Not everything is collectible the same way. Periodic child support can be collected by the agency; school fees, insurance premiums and other payments to third parties are enforced differently — and whether they are enforceable at all can turn on how the agreement was drafted and registered.
- Where there has been family violence or financial control, Private Collect is the wrong choice no matter how cooperative the other parent appears on paper. Agency collection removes the need for any contact about money — and the receiving parent can choose it without the other parent’s consent.
How we can help
Most of the traps in this area are invisible until years later — which is exactly when they can no longer be fixed. This is work we do every day:
- Advising before you agree to a parenting schedule — modelling how a proposed care arrangement affects the assessment and your Family Tax Benefit, so the numbers are known before the deal is done.
- Drafting and reviewing child support agreements — and providing the independent legal advice and solicitor’s certificate the law requires before a binding agreement can exist. If the other parent’s lawyer has sent you an agreement to sign, have it reviewed before you sign, not after.
- Finalising everything together — parenting consent orders, property settlement and a child support agreement as one coherent package.
- Change of assessment, objections and recovery — where income is disputed or understated, where a Services Australia decision needs to be challenged, or where arrears must be pursued through the courts.
We are based in Brisbane and assist clients in both English and Mandarin.
Useful links
- Child Support Guide — how Services Australia applies the formula, agreements and collection: guides.dss.gov.au/child-support-guide
- Services Australia — applying for an assessment and changing your collection method: servicesaustralia.gov.au/child-support-assessment
- Legislation — Child Support (Assessment) Act 1989 (Cth) and Child Support (Registration and Collection) Act 1988 (Cth): legislation.gov.au
- If you are not safe — DVConnect Womensline 1800 811 811, Mensline 1800 600 636; in an emergency call 000.
This article is general information only and does not take account of your particular circumstances. It is not legal advice and should not be relied on as such. Child support rates, thresholds and Services Australia policy change regularly.
Visit or Contact Us
📍 68 Bryants Road, Shailer Park QLD 4128
📞 (07) 2810 5666
🌐 www.wglawyers.com.au
✉ info@wglawyers.com.au
Disclaimer
This article is general information only and does not constitute legal advice under Australian law. For advice specific to your situation, please contact W & G Lawyers. For further details, please click here to view our disclaimer.