Reasonable and necessary

What is reasonable and necessary in the NDIS?

"Reasonable and necessary" is the legal test the NDIA uses to decide which supports to fund in a participant's NDIS plan. Under section 34 of the NDIS Act, a support is only funded if it meets every criterion: it helps the participant pursue their goals and take part in social and economic life, is value for money, is effective and beneficial, takes account of what family and community can reasonably provide, is most appropriately funded by the NDIS, and is an NDIS support.

In plain terms, "reasonable" is about whether the support is fair and sensible to fund: is the cost proportionate, and is it the NDIS's job rather than another system's? "Necessary" is about whether the participant actually needs the support because of their disability to live their life and pursue their goals. A support that would be nice to have, or that everyone needs regardless of disability, generally won't pass.

You'll hear the phrase everywhere in the NDIS: in planning meetings, in therapist reports ("this support is reasonable and necessary because…"), in NDIA decision letters, and in internal review requests. It applies to every NDIS plan and every participant.

The reasonable and necessary criteria

The criteria are set out in section 34(1) of the NDIS Act 2013 and explained in the NDIA's operational guideline on what supports the NDIS can fund. The NDIA must be satisfied that all of them are met. A support that fails one criterion isn't funded, however strongly it meets the others.

The NDIS (Supports for Participants) Rules 2013 add more detail on how some of these criteria are applied, such as value for money and the responsibilities of other service systems.

How the NDIA applies reasonable and necessary

The NDIA applies the criteria when it builds or reassesses a plan, and again at internal review if the participant disagrees. The decision is made by an NDIA delegate, not by a local area coordinator or provider, although both can help collect information.

A few principles shape most decisions:

• Disability-related need. The support must respond to needs that come from the participant's disability, not costs everyone has.
• Whole of life view. The NDIA looks at what's already in place, including informal supports and mainstream supports, and funds what's needed on top.
• Evidence, not diagnosis. Two people with the same diagnosis can have very different reasonable and necessary supports because their functional needs, goals and circumstances differ.
• Price and quantity both count. A support can be reasonable and necessary at a certain intensity (for example, a number of therapy hours) but not at a higher one.

Reasonable and necessary vs NDIS supports

Since 3 October 2024 there are two separate gates. NDIS supports is a legal category: whether NDIS funding can ever pay for this kind of thing. Reasonable and necessary is an individual test: whether the NDIA should fund it for this person, at this level. Being an NDIS support is now one of the reasonable and necessary criteria, so a support must pass both.

A related idea is stated supports: funding the NDIA ties to a specific support or way of delivery in the plan, such as specialist disability accommodation or certain assistive technology. And replacement supports are items outside the NDIS supports list that the NDIA can approve, in limited cases, instead of an NDIS support.

How to show a support is reasonable and necessary

Most disputes about funding come down to evidence. Whether you are a participant, family member, support coordinator or therapist, these steps make a request easier to approve:

1. Start with the goal. Name the plan goal the support relates to, in the participant's own words where possible.
2. Describe functional impact. Explain what the person can't do, or can only do with help, because of their disability, and how often.
3. Show what's already there. Describe family, community and mainstream supports, and what's reasonable to expect of them. A carer who is burning out is relevant evidence.
4. Compare options. Show alternatives considered and why the recommended support is better value, including any longer-term savings.
5. Link to good practice. Ask the treating professional to explain why the approach is effective for this person.
6. Be specific. State the type, frequency and duration, such as hours a week of support, sessions of therapy, or a specific piece of equipment with quotes where needed.

Providers can help by keeping clear progress notes that show how supports are working towards goals. That record becomes evidence at the next plan reassessment. The free NDIS progress note writer can help structure notes around goals.

What providers need to know

Providers don't decide what is reasonable and necessary, but the test shapes their work in three ways:

• You can only deliver what's funded. Before agreeing to a support, check it is in the participant's plan and in the right budget, and record it in the service agreement.
• Your reports become evidence. Therapy reports, functional assessments and progress summaries are often what the NDIA relies on at reassessment. Write them to the criteria: goals, functional impact, options and outcomes.
• Value for money applies to you too. Funding is priced using the NDIS pricing arrangements and price limits, so quotes and recommendations should be realistic. Check current limits in the free NDIS price guide.

If you disagree with a reasonable and necessary decision

Decisions about which supports are in a plan are reviewable. You can ask the NDIA for an internal review within 3 months of the decision, and if you still disagree, apply to the Administrative Review Tribunal, generally within 28 days of the internal review decision (NDIA: how to request a review). Focus the request on the criterion the NDIA said wasn't met, and add evidence that addresses it.

Changes to reasonable and necessary (2024–2028)

The test is evolving with the NDIS reforms:

• 3 October 2024: amendments added the requirement that a support be an NDIS support under the section 10 lists.
• New framework plans: under the 2024 amendments, these plans are built from a support needs assessment, and a method set in the rules calculates the participant's budget as a whole rather than costing each support line by line. The government has said new framework planning is expected to start gradually from 1 April 2027 (Department of Health, Disability and Ageing).
• 2026: the NDIS Amendment (Securing the NDIS for Future Generations) Act 2026 is part of a package that includes clarifying the supports the NDIS funds. See the NDIA's Securing the NDIS page for what has started and when.

Until a participant moves to a new framework plan, their supports are still decided support by support against the criteria above.

Common misunderstandings

• "Reasonable and necessary means the best possible support." It means the support that meets the criteria, including value for money, not the most expensive option.
• "If my doctor says I need it, it's reasonable and necessary." Professional evidence matters, but the NDIA must still be satisfied about every criterion.
• "Family support counts against me." The NDIA considers what's reasonable to expect of family, not everything family could possibly do.
• "Once funded, always funded." Each plan is a fresh decision based on current needs and evidence.
• "It's a separate form to fill in." It's a legal test applied to the evidence you give at planning or reassessment.