NDIS reasonable and necessary supports, explained.
You delivered a support. The participant wanted it, the worker provided it, and then the claim came back — the support was not in the plan. 'Reasonable and necessary' is the test the NDIA runs before a support gets funded, and it has already been applied by the time you see a plan. Your job is to deliver and bill within what passed that test, not to re-run it yourself. Claiming against supports that are not in the plan is the most common cause of unexpected rejections at audit.
A support is reasonable and necessary if it relates to the participant's disability, represents value for money, is likely to be effective, helps them pursue their plan goals, and is most appropriately funded by the NDIS rather than another system. All criteria must be met — the NDIA decides, not the provider.
What the test is — and why it matters
The NDIS does not fund every support a person might benefit from. It funds reasonable and necessary supports — supports that meet a specific set of criteria set out in section 34 of the National Disability Insurance Scheme Act 2013. When the NDIA builds or reviews a participant's plan, a planner or delegate applies these criteria to decide what gets funded and how much.
It matters because the funded supports in a plan are the boundary of what the scheme will pay for. A support that sits outside that boundary is not funded — no matter how genuinely useful it might be. For participants, the test shapes their plan. For providers, it shapes what you can legitimately roster and claim.
Importantly, the test is applied case by case. The same type of support can be reasonable and necessary for one person and not for another, because it depends on that individual's disability, goals, and circumstances. There is no fixed list of "approved" supports that applies to everyone.
The criteria a support must meet
To be funded, a support generally needs to satisfy each of the following. The NDIA weighs them together — a support that clearly fails one of them is unlikely to be funded, even if it meets the others.
It relates to the participant's disability
The support must be connected to the person's disability and the functional impact it has on their daily life — not to a need that anyone might have regardless of disability.
It represents value for money
The cost of the support must be reasonable relative to the benefits it delivers, and relative to the cost of alternative supports that would achieve a similar outcome.
It is likely to be effective and beneficial
The support should be effective and beneficial for the participant, having regard to current good practice. In other words, there should be reason to believe it actually works.
It helps the participant pursue their plan goals
The support should help the person work towards the goals, objectives, and aspirations recorded in their plan, and support their social and economic participation.
It is most appropriately funded by the NDIS
The support should not be something it is reasonable to expect family, carers, or informal networks to provide, and it should not be more appropriately funded by another service system — such as health, education, or housing.
It is not an everyday living cost unrelated to disability
Day-to-day living costs a person would have regardless of their disability — rent, groceries, ordinary utility bills — are not reasonable and necessary supports. Only the additional costs that arise directly from disability needs are in scope.
What it means for providers
Here is the part that catches providers out: the reasonable and necessary decision has already been made by the time you start delivering. The NDIA applied the test when it built the participant's plan, and the result is the funded supports written into that plan. Your job is to deliver and claim within those supports — not to re-run the test yourself.
Read the plan before you commit to a support
Check which support categories are funded, how much sits in each, and whether any supports are stated (locked to a specific item) rather than flexible. A support that is not in the plan is not funded — even if everyone involved agrees it would help.
Do not assume "helpful" equals "covered"
A support being beneficial is not the same as it being reasonable and necessary. If something useful sits outside the funded supports, the path is a plan review or reassessment with the NDIA — not quietly claiming it against an unrelated budget.
Claim against the right category
Match what you deliver to the funded support and support category in the plan, and keep your claims within the approved budget. Claiming a support against funding that was never intended for it is a common cause of audit findings and clawbacks. NDIS case notes software that records each note against the funded support makes that match easy to evidence at audit.
The NDIA decides — confirm against the plan
This guide is general information, not advice about a specific participant or support. The reasonable and necessary criteria are applied by the NDIA on a case-by-case basis, and the outcome for any individual depends on their disability, goals, and circumstances. Always confirm what is funded against the participant's actual plan, and check directly with the NDIA or the relevant NDIS guidance before relying on a support being covered.
For NDIS providers using practice management software
Rostrel links every service booking directly to the funded support categories and budgets in a participant's plan, so you can only roster and claim against what the NDIA has already approved as reasonable and necessary. When a participant's funding is running low in a category, Rostrel flags it before delivery — not after a claim is rejected. That means no accidental claims outside approved supports, and a clean audit trail showing every line item maps back to the correct funded category.
Frequently asked questions
What does "reasonable and necessary" mean in the NDIS?
It is the legal test the NDIA applies to decide whether a support is funded in a participant's plan. The support must relate to the person's disability, represent value for money, be likely to be effective and beneficial, help them pursue their plan goals, and not be something more appropriately funded by family, carers, or another service system such as health or education. The criteria come from section 34 of the NDIS Act.
Who decides whether a support is reasonable and necessary?
The NDIA decides. A planner or delegate applies the criteria when building or reviewing a participant's plan, and the funded supports are then set out in the plan itself. Providers and participants do not make this decision — they deliver and claim within the supports the NDIA has already approved.
Does reasonable and necessary mean the same as helpful?
No. A support can be genuinely helpful and still not be reasonable and necessary under the NDIS. The test is narrower — it asks whether the support relates to the disability, is value for money, is likely to be effective, and is most appropriately funded by the NDIS rather than another system. A support that fails any of these can be declined even if it would help.
Are everyday living costs reasonable and necessary?
Generally no. Day-to-day living costs a person would have regardless of their disability — such as rent, groceries, and ordinary utility bills — are not reasonable and necessary supports and are not funded by the NDIS. The exception is the additional cost of a support that is directly attributable to a person's disability needs.
What does reasonable and necessary mean for providers?
You deliver and claim only within the supports the NDIA has already funded as reasonable and necessary in the participant's plan. Do not assume a support is covered just because it seems beneficial — read the plan, check the funded support category and any stated items, and bill within what was approved.
Bill within what was approved
Rostrel keeps delivery and claims tied to the funded supports in each participant's plan, so what you roster and bill stays inside the budget the NDIA has already approved — fewer surprises at audit, and nothing claimed against the wrong category.
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