Reasonable and Necessary Supports: 10 Questions Answered

Confused about what counts as reasonable and necessary under the NDIS? Here are plain-English answers to the 10 questions participants and families ask most.

If you've ever wondered why a particular support was funded in your NDIS plan - or why one wasn't - the answer almost always comes back to the same phrase: "reasonable and necessary." Understanding what those two words actually mean in practice can make a real difference when you're preparing for a planning meeting, reviewing your plan, or helping a family member navigate the scheme.

This article answers the 10 questions Australians ask most about reasonable and necessary supports, in plain English, with no jargon.

What does "reasonable and necessary" actually mean?

Q. What does it mean for an NDIS support to be "reasonable and necessary"?

Under the National Disability Insurance Scheme Act 2013, a support must meet a set of criteria before the NDIA will fund it. The term "reasonable and necessary" is the shorthand for those criteria, but it's not a single test - it's a combination of several considerations that the NDIA weighs together.

In broad terms, a support is reasonable and necessary if it relates to your disability, helps you pursue your goals or increase your independence, represents value for money, and is something the NDIS - rather than another system like health or education - is responsible for funding. Every one of those elements matters. A support that ticks some boxes but not others may still be declined.

It's worth knowing that the NDIA considers your individual circumstances, not just the type of support. The same item or service might be funded for one participant and not another, depending on how each person's disability affects their daily life and what other supports are available to them.

What are the specific criteria the NDIA uses?

Q. What are the exact criteria a support must meet to be considered reasonable and necessary?

The NDIS Act sets out several criteria that the NDIA applies when deciding whether to fund a support. The support must:

Be related to your disability - it must address a need that arises from your disability, not a general life expense.
Not include day-to-day living costs that are not related to your disability support needs - for example, rent, groceries or utility bills.
Represent value for money - the cost must be reasonable compared to the benefit it delivers, and compared to alternatives.
Be likely to be effective and beneficial - there should be evidence or reasonable expectation that the support will work for you.
Take into account what is reasonable to expect families, carers and communities to provide - informal supports are considered.
Not be more appropriately funded or provided through another system - such as the health system, education system, or aged care.

The NDIA considers all of these together. Missing any one of them can mean a support isn't funded, even if it seems clearly helpful on the surface. If you're unsure how your request stacks up, a support coordinator can help you frame it clearly before your planning conversation.

Does "reasonable and necessary" mean the cheapest option?

Q. Does the NDIA only fund the cheapest possible support?

Not exactly - but cost is genuinely part of the picture. "Value for money" doesn't mean the NDIA will only ever fund the lowest-cost option. It means the cost needs to be proportionate to the benefit, and it needs to be reasonable compared with alternative ways of meeting the same need.

For example, if a more expensive piece of assistive technology will allow you to live more independently and reduce the need for paid support workers over time, that cost-benefit calculation can work in your favour. On the other hand, if a less expensive option would meet the same need just as well, the NDIA is unlikely to fund the pricier version simply because you prefer it.

The key is being able to articulate why the support you're requesting is the right fit for your goals and circumstances, not just that it's helpful in a general sense.

What supports are excluded no matter what?

Q. Are there supports the NDIS will never fund, even if they seem disability-related?

Yes. The NDIS Rules specify categories of support that are excluded from NDIS funding regardless of a participant's disability. These include:

Day-to-day living costs not related to disability support needs (rent, food, clothing, standard household bills).
Supports that are the responsibility of another government system - for example, surgery, hospital care, or school-based education supports that fall under state government obligations.
Supports that are illegal or would expose a provider to legal liability.
Supports that are not related to the participant's disability.
Supports that are contrary to NDIS Rules or the NDIS Act.

It's also worth noting that some supports sit in a grey area between the NDIS and other systems - for example, some allied health services. In those cases, the NDIA looks at whether the support is primarily disability-related or primarily a health treatment, and which system is most responsible. Navigating those grey areas is one of the reasons a good support coordinator can be so valuable.

Does the support have to be provided by a registered provider?

Q. Does a support need to come from a registered NDIS provider to be considered reasonable and necessary?

No - whether a support needs to come from a registered provider depends on how your plan is managed, not on the reasonable and necessary criteria themselves. The reasonable and necessary test is about whether the NDIA will fund the support at all. The question of who delivers it is a separate one.

If your plan is agency-managed, you can only use NDIS-registered providers. If your plan is plan-managed or self-managed, you have more flexibility to use providers who aren't registered with the NDIS Commission, as long as those providers still meet appropriate quality and safety standards.

When you're comparing provider options, it helps to understand what verification and safety checks different providers have in place. You can learn more about what OpenWay's verification process covers to help you assess providers confidently.

Can my support needs change what's considered reasonable and necessary?

Q. If my disability needs change, can something that wasn't funded before become reasonable and necessary?

Yes, absolutely. The reasonable and necessary assessment is always based on your current circumstances, goals and support needs. If your disability has progressed, your living situation has changed, or you've taken on new goals, a support that wasn't appropriate before might now clearly meet the criteria.

This is one of the most important reasons to request a plan review when your circumstances change, rather than waiting for your scheduled review date. The NDIA can conduct an unscheduled review if there's been a significant change in your situation.

It also works the other way. If informal supports become available - for example, a family member moves closer and can assist with tasks they couldn't before - the NDIA may take that into account and reduce funding for those supports. The assessment is always meant to reflect your real, current situation.

How does the NDIA decide what's "not the role of the NDIS"?

Q. How does the NDIA decide when something is another system's responsibility rather than the NDIS's?

This is one of the trickiest parts of the reasonable and necessary test, and it catches many participants off guard. The NDIS is designed to fund disability-specific supports, not to replace services that all Australians can access through mainstream systems like Medicare, public hospitals, public schools, or state-funded community services.

The NDIA looks at whether the support is something that would typically be provided by another government system, regardless of disability. If a support is something any Australian would access through the health system - for example, specialist medical treatment - the NDIS is unlikely to fund it, even if the need arises from a disability.

Where it gets complicated is when a support sits at the boundary. For example, some therapy supports are funded by the NDIS while others fall under Medicare. The NDIA considers the primary purpose of the support and whether there's a clear gap that only the NDIS can fill. Getting independent advice from a support coordinator or a disability advocate can help you understand which system should be responsible for a particular support.

Does "reasonable and necessary" apply to all three plan budget categories?

Q. Does the reasonable and necessary test apply to all types of NDIS funding - core, capacity building and capital?

Yes, the reasonable and necessary criteria apply across all three NDIS budget categories: Core Supports, Capacity Building Supports, and Capital Supports. The same underlying principles apply regardless of which budget the support falls into.

That said, how the criteria are applied can feel different depending on the category. Capital supports - like assistive technology or home modifications - often require more detailed evidence, quotes and assessments because the costs are higher and the decisions are less reversible. Capacity building supports need to demonstrate that they're building skills or independence, not just providing ongoing assistance. Core supports tend to be the most flexible in how they're used, but they still need to be disability-related and appropriate.

If you're unsure which category a support falls into, or how to make the case for it in your plan, browsing how OpenWay is designed to help NDIS participants may give you a useful starting point for finding the right provider to support that process.

What evidence helps when requesting a support?

Q. What kind of evidence should I provide to support a request for funding?

Strong evidence makes a significant difference when you're requesting a support that isn't already in your plan, or when you're seeking to increase funding. The NDIA looks for evidence that:

Clearly describes how your disability affects your ability to do the thing the support is meant to help with.
Explains why this particular support (rather than an alternative) is the right fit.
Is provided by a relevant professional - for example, an occupational therapist, physiotherapist, speech pathologist, or your treating specialist.
Connects the support to your goals in your plan.

Functional assessments are particularly useful because they describe what you can and can't do, rather than just naming a diagnosis. A diagnosis alone rarely tells the NDIA enough about your day-to-day support needs. If you're working with a support coordinator, they can help you identify the right professionals to gather evidence from and make sure the evidence is framed in a way that addresses the NDIA's criteria.

You can browse allied health and support coordination providers on OpenWay to find professionals who can help you build a strong evidence base for your plan.

What can I do if I disagree with the NDIA's decision?

Q. What are my options if the NDIA decides a support isn't reasonable and necessary and I disagree?

You have the right to challenge an NDIA decision you believe is wrong. The process starts with an internal review - you request that the NDIA review its own decision. This is called a "review of a reviewable decision" and you generally have three months from the date of the decision to request one. You don't need a lawyer to do this, but having clear evidence and a well-structured written submission helps.

If the internal review doesn't go in your favour, you can take the matter to the Administrative Appeals Tribunal (AAT), which is an independent body that can review NDIA decisions. Disability advocacy organisations across Australia can support you through this process at no cost. Your state or territory has at least one funded disability advocacy service.

It's worth noting that many disputes about reasonable and necessary decisions are resolved at the internal review stage, particularly when new or better evidence is provided. If you were declined because the evidence wasn't strong enough, gathering more detailed functional assessments before requesting a review can make a real difference.

Frequently asked

Is "reasonable and necessary" the same as "medically necessary"?

No. "Medically necessary" is a term used in healthcare settings and relates to clinical need. "Reasonable and necessary" is an NDIS-specific legal standard that covers a broader range of disability support needs - not just medical ones - and includes considerations like value for money, the role of informal supports, and the boundaries between the NDIS and other systems. A support can be medically necessary without being reasonable and necessary under the NDIS, and vice versa.

Can a support coordinator help me argue that a support is reasonable and necessary?

Yes. Support coordinators are specifically trained to help participants understand the NDIS framework, gather appropriate evidence, and communicate support needs effectively to the NDIA. They can't make decisions on the NDIA's behalf, but they can help you put your best case forward. Finding a support coordinator who knows your disability type well can make a significant difference. You can explore the OpenWay support coordinator workspace to understand how coordinators use the platform.

Does the reasonable and necessary test apply differently to children?

The same legal criteria apply, but the NDIA considers age-appropriate activities and development when assessing supports for children. For young children, the NDIA also takes into account what families would typically provide as part of normal parenting, which can affect what's funded. Early intervention supports for children under seven are assessed under a slightly different framework focused on outcomes and developmental goals, though the reasonable and necessary principles still apply broadly.

How OpenWay can help

Understanding the reasonable and necessary criteria is one thing - finding providers who can actually deliver the supports in your plan is another. OpenWay is a free-to-use marketplace for NDIS participants, families and support coordinators to browse, compare and enquire with disability service providers across Australia.

You can browse NDIS providers by support type and location to find allied health professionals, support coordinators, daily living providers and more. Provider profiles include information about the supports they offer, the areas they service, and the registration status - so you can make informed decisions without having to ring around.

OpenWay is free for participants and families to use. Providers list on the platform to make themselves discoverable, and you can send enquiries directly through the site. There's no obligation and no cost to you to explore your options.

OpenWay is not part of the NDIS, NDIA or NDIS Commission. Final scope, pricing, travel, cancellation rules and non-face-to-face charges must be confirmed in a written service agreement between the participant (or their authorised support person) and the provider.

This article was written by OpenWay editorial with AI assistance. We review for accuracy + tone but the framing rules of the NDIS apply: nothing here is medical, legal or financial advice. Always check the NDIS Commission and your plan for the latest rules.