Information Centre · Family Law
Child Support Assessments and Private Agreements in Australia
How administrative child support assessments work in Australia, and how they relate to limited and binding child support agreements, change of assessment, collection and enforcement.
Key points
- Child support in Australia is principally governed by the Child Support (Assessment) Act 1989 (Cth) and the Child Support (Registration and Collection) Act 1988 (Cth), and is administered by Services Australia (Child Support).
- Administrative assessments apply a statutory formula that takes into account each parent's adjusted taxable income (with a self-support amount deducted), care percentage and cost percentage, the costs of the child bracket, and any relevant dependent children or multi-case circumstances; the applicable amounts are set and indexed by the legislation.
- Estimates of income may be lodged and reconciled in defined circumstances, and changes of care may be notified to Services Australia and may prospectively affect the assessment.
- A parent may apply for a change of assessment on statutory grounds — including high costs of enabling contact, high costs of caring for or educating the child, the child's own income or resources, and the parent's income, property, financial resources or earning capacity — with outcomes decided on the facts and evidence.
- Limited child support agreements do not require independent legal advice and have statutory termination pathways; binding child support agreements require each party to obtain independent legal advice from an Australian legal practitioner and are generally harder to terminate.
- Collection may be private or via Services Australia; statutory enforcement mechanisms include employer withholding, tax refund interception and departure prohibition orders in relevant cases. Child support is distinct from parenting orders under Part VII of the Family Law Act 1975 (Cth) and from spousal maintenance under s 74 or s 90SE (and from adult child maintenance under s 66L).
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Child support in Australia is principally governed by the Child Support (Assessment) Act 1989 (Cth) and the Child Support (Registration and Collection) Act 1988 (Cth), and is administered by Services Australia (Child Support). Private agreements are available in two forms — limited and binding — each with its own statutory requirements.
Administrative assessment
Under the Assessment Act, Services Australia calculates child support using a statutory formula that considers each parent's adjusted taxable income, care percentage and cost percentage, the costs of the child bracket (based on the parents' combined child support income and the number and ages of the children), and any relevant dependent children or multi-case circumstances. The applicable amounts are set and indexed by the legislation and should be confirmed with Services Australia rather than assumed.
Estimates and change of care
A parent may lodge an estimate of income in defined circumstances, and estimates may be reconciled against the parent's later tax outcome. Care changes can be notified to Services Australia and may prospectively affect the assessment. Timely notification is generally important because retrospective adjustments are limited by the Act.
Change of assessment
A parent may apply for a change of assessment on statutory grounds. These include high costs of enabling contact with the child, high costs of caring for or educating the child, the child's own income or resources, and the parent's income, property, financial resources or earning capacity, among others. Whether a ground is made out is fact-specific and evidence-based.
Limited and binding agreements
A limited child support agreement must be in writing, lodged with Services Australia and generally requires an administrative assessment to be in place. It does not require independent legal advice but has statutory termination pathways.
A binding child support agreement can be made without an administrative assessment. Under s 80C(2) of the Child Support (Assessment) Act 1989 (Cth), each party must receive independent legal advice from a legal practitioner before that party signs, covering the effect of the agreement on the party's rights and the advantages and disadvantages, at the time the advice is given, of making the agreement. The agreement must contain the required statement and the annexure must contain the adviser's signed certificate that the advice was provided. After signing, either the original agreement or a copy must be given to each party. Binding agreements are generally harder to terminate than limited agreements. Whether an agreement is appropriate, and in what form, depends on the parties' circumstances and objectives.
Non-periodic and lump-sum arrangements are permitted in defined statutory circumstances and may be credited against periodic liability under the Act; the detail matters and should be confirmed before commitments are made.
Collection and enforcement
Parents may collect privately or use Services Australia collection under the Registration and Collection Act. Statutory enforcement mechanisms include employer withholding, interception of tax refunds, departure prohibition orders in relevant cases and other tools. Courts also have specific roles, including departure orders in certain proceedings. Reciprocal arrangements exist with a number of overseas jurisdictions but not all.
Related legal frameworks
Child support (financial support of children) is distinct from parenting orders under Part VII of the Family Law Act 1975 (Cth), which concern the care, welfare and development of the child. See our guide to parenting orders.
Spousal maintenance under s 74 or s 90SE and adult child maintenance under s 66L are distinct from child support. See our guide to spousal maintenance.
Frequently Asked Questions
How is administrative child support assessed?
Under the Child Support (Assessment) Act 1989 (Cth), Services Australia (Child Support) assesses child support using a statutory formula. The formula takes into account each parent's adjusted taxable income (with a self-support amount deducted), each parent's care percentage and cost percentage, the number and ages of the children, and any relevant dependent children or multi-case circumstances. The applicable amounts are set and indexed by the legislation; the actual figures should be checked with Services Australia rather than assumed.
How does care percentage affect the assessment?
Care percentage is the proportion of nights (or, in some cases, equivalent care) each parent is expected to provide to the child. Care percentage is converted to a cost percentage under the Act, which then feeds into the formula. Changes in the actual care pattern can be notified to Services Australia and may alter the assessment prospectively.
Can a parent lodge an estimate of income?
Yes. Under the Assessment Act, a parent may in certain circumstances lodge an estimate of income for a period, and the assessment can be recalculated when the actual income is known. Estimates are subject to statutory rules and may be reconciled against the parent's later tax outcome; under- and over-estimates can produce adjustments and, in some cases, penalties.
What is a change of assessment?
A parent may apply to Services Australia for a change of assessment on statutory grounds set out in the Act — for example, high costs of enabling contact, high costs of caring for or educating the child, the child's own income or resources, the parent's income, property, financial resources or earning capacity, or that the assessment is unjust and inequitable because of the special circumstances of the case. Applications are decided on the facts and evidence; outcomes are not guaranteed.
What is a limited child support agreement?
A limited child support agreement under Part 6 of the Assessment Act is a written agreement between the parents that must be lodged with Services Australia and that requires an administrative assessment to be in place. It does not require independent legal advice, but may be terminated in the ways set out in the Act (including by written agreement, by a new agreement or under statutory triggers relating to changes in the notional assessment or after a set period). It is not always the best structure — appropriateness depends on the facts.
What is a binding child support agreement?
A binding child support agreement is a more formal agreement that can be made even without an administrative assessment. Under s 80C(2) of the Child Support (Assessment) Act 1989 (Cth), each party must receive independent legal advice from a legal practitioner before that party signs, covering the effect of the agreement on the party's rights and the advantages and disadvantages, at the time the advice is given, of making the agreement. The agreement must contain the required statement and the annexure must contain the adviser's signed certificate that the advice was provided. After signing, either the original agreement or a copy must be given to each party. Binding agreements are generally more difficult to terminate than limited agreements and may include periodic and non-periodic provisions. Independent legal advice before signing is a statutory requirement, not optional.
How are non-periodic or lump-sum arrangements treated?
The Assessment Act permits non-periodic payments, lump-sum payments and payments in kind in defined circumstances, subject to the Act and any relevant agreement. Credit against periodic liability is governed by the Act and Services Australia policy. Whether a proposed arrangement is available, appropriate and reflected correctly in the assessment is fact-specific and should be checked before commitments are made.
How is child support collected and enforced?
Parents may collect privately or use Services Australia collection under the Child Support (Registration and Collection) Act 1988 (Cth). Where Services Australia collects, statutory mechanisms include employer withholding, tax refund interception, departure prohibition orders in relevant cases and other enforcement tools. Courts also have specific roles, including departure orders in certain proceedings. Overseas reciprocal arrangements exist with a number of countries but not with every jurisdiction.
How is child support different from parenting orders and spousal maintenance?
Child support is the financial support of a child governed by the Assessment Act and Registration and Collection Act, and is administered by Services Australia. Parenting orders under Part VII of the Family Law Act 1975 (Cth) deal with the care, welfare and development of the child, not the periodic financial contribution. Spousal maintenance under s 74 or s 90SE of the Family Law Act concerns support of a former spouse or de facto partner; adult child maintenance under s 66L is a distinct and narrower statutory pathway. Each has its own criteria, evidence requirements and outcomes.
How Parke Lawyers Can Help
Parke Lawyers acts for parents across Australia on Child Support Assessments, Binding and Limited Child Support Agreements, departure applications, objections and enforcement, alongside parenting and property work through our Family Law team. Engage us early — the terms locked into a binding agreement are difficult to unwind later.
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Our family law team can advise on child support assessments, change of assessment applications and limited or binding child support agreements.
This article is general information only and does not constitute legal advice. Please obtain advice tailored to your circumstances.