If you’ve spent any time in the NDIS, you’ve heard the phrase “reasonable and necessary.” It’s the test that sits behind every funding decision, whether a support gets funded or not comes down to whether it meets this standard. Yet it’s rarely explained clearly. Understanding what it actually means is one of the most useful things a participant can do, because it tells you how to frame what you need. Here’s the plain-language guide.
What “Reasonable and Necessary” Means
“Reasonable and necessary” is the legal test the NDIS uses to decide whether to fund a support. It remains the funding test under the reformed scheme. In plain terms, a support has to be both reasonable (fair, and appropriate given your situation) and necessary (genuinely required because of your disability) to be funded.
It’s not about funding everything a person might want, or everything that would be nice to have. It’s about funding what you genuinely need, because of your disability, to live your life and pursue your goals. Understanding that distinction is the key to the whole thing.
The Criteria Behind the Test
A support is assessed against a set of criteria. Broadly, to be reasonable and necessary, a support should: relate to your disability; not include day-to-day living costs unrelated to your support needs; represent value for money; be likely to be effective and beneficial for you; and take into account support provided by family, carers, networks and the community.
It also needs to be the kind of support the NDIS is meant to fund, rather than something that’s the responsibility of another system like health, education or housing. This is where the “boundaries” between the NDIS and mainstream services matter, and those boundaries are being made clearer under the reforms.
Why Framing Matters So Much
Here’s the practical heart of it: the same support can be funded or refused depending on how clearly it’s connected to your disability-related need and your goals. A support described vaguely (“I’d like some help getting out more”) is far weaker than one tied explicitly to functional need and a goal (“I need support to use public transport independently so I can attend my TAFE course, which my disability currently prevents”).
The reforms put even greater weight on functional impact, how your disability actually affects your daily life, so framing your supports in those terms is what gives them the best chance. If understanding which budget a support belongs to would help you frame it, our free NDIS budget explainer walks through the three budgets and what each funds.
How to Show a Support Is Reasonable and Necessary
Several things strengthen your case. Connect the support directly to your disability, showing why you need it because of your functional impairment. Connect it to a goal in your plan, demonstrating what it helps you achieve. Provide evidence from your treating professionals that documents the need and the support’s likely benefit. Show it’s value for money, that it’s an effective, appropriate way to meet the need. And describe your functional reality honestly, including your hardest days, since that’s what the test actually responds to.
Evidence and clear connection to disability-related need are what make a support defensible, at planning, at reassessment, and on review.
What It Doesn’t Cover
Being clear-eyed helps too. Reasonable and necessary generally won’t fund: everyday living costs everyone has (regardless of disability); supports that are the responsibility of another system (like general health care or education); things that aren’t related to your disability; or supports that aren’t effective or good value. Knowing these boundaries helps you focus your energy on the supports that genuinely qualify, rather than ones likely to be refused. The official criteria are on the NDIS reasonable and necessary page.
The Bottom Line
“Reasonable and necessary” is the test behind every NDIS funding decision: a support must be genuinely required because of your disability, connected to your goals, effective, and good value, and not the job of another system. The same need can be funded or refused depending on how clearly you connect it to your disability and evidence it. Frame your supports in terms of functional need and goals, back them with evidence, and you give them the best chance, at planning, reassessment or review. This is general information, not disability, legal or financial advice.
Epik Wire covers the NDIS in plain language for participants and families. Subscribe to our newsletter to stay informed.
