What "Reasonable and Necessary" Actually Means Under the NDIS

What Is the NDIS Reasonable and Necessary Test? Section 34 Explained

"Reasonable and necessary" is the phrase that governs every single dollar of NDIS funding. It's the legal test under Section 34 of the National Disability Insurance Scheme Act 2013. If a support doesn't meet this test, the NDIS won't fund it — no matter how helpful it might be.

Across the $40 billion+ scheme serving 650,000+ participants, this test is the gatekeeper. Understanding it — and learning how to frame your requests through its lens — is probably the most valuable skill any participant can develop. If you're preparing for your planning meeting, our NDIS planning meeting guide shows how to use these criteria to advocate for the supports you need.

The Six NDIS Reasonable and Necessary Criteria Every Support Must Meet

For a support to be funded, it must meet all six of these criteria:

1. The support must be related to your disability

This is straightforward for some impairments (a wheelchair for someone who can't walk) and trickier for others (a gym membership for someone with a psychosocial disability — is that disability-related or general health?). The support must directly address the functional impact of your impairment, not just improve your general wellbeing.

2. The support must not be day-to-day living costs

The NDIS does not pay for rent, groceries, utility bills, or everyday expenses that everyone has. However, it will fund the additional costs created by your disability — such as the extra electricity to power a ventilator, or the cost of having meals prepared by a support worker because you can't cook safely.

3. The support must represent value for money

The NDIA compares the cost of the support against the benefit it delivers, and against alternative ways to achieve the same outcome. A $5,000 custom piece of equipment might be funded instead of a $20,000 one with unnecessary features. The NDIA isn't required to fund the "best" option — just the one that achieves the outcome at reasonable cost.

4. The support must be effective and beneficial

There must be evidence that the support actually helps. For established therapies like physiotherapy and occupational therapy, this is rarely questioned. For emerging or alternative therapies, the NDIA may require stronger evidence of effectiveness. Anecdotal reports alone usually aren't enough.

5. The support must take into account informal supports

The NDIA considers what family, friends, and community can reasonably provide. If your partner helps you shower every morning, the NDIA won't fund a support worker for that — unless the arrangement is unsustainable, or it's unreasonable to expect your partner to continue. This is where many disputes arise: the NDIA often overestimates what family can provide long-term.

6. The support must be most appropriately funded by the NDIS

If another government system is responsible — Medicare, the education system, the health system, or state disability programs — the NDIS won't fund it. For example, the NDIS won't pay for a teacher's aide at school (that's the education department's job), but it might fund therapy that helps a child participate in school.

NDIS Reasonable and Necessary Examples: What Gets Funded and What Doesn't

Example 1: Gardening service

• Fails. Mowing the lawn is a day-to-day living cost (criterion 2), not disability-specific. The NDIS won't fund it — even if your disability prevents you from doing it yourself.

Example 2: Support worker for community access

• Passes. If your disability prevents you from leaving home alone safely, a support worker to accompany you to community activities is related to your disability (criterion 1), effective (criterion 4), and not something family can reasonably provide every time (criterion 5). It's funded.

Example 3: iPad for communication

• Passes — with caveats. For someone with a speech impairment who uses it as a communication device, it passes all six criteria. For someone who just wants an iPad for entertainment, it fails criterion 1 (not disability-related) and criterion 4 (no evidence of benefit for the disability). The NDIA will fund the device if it's listed as assistive technology by an allied health professional.

Example 4: Holiday travel

• Fails. A holiday itself is a day-to-day living cost. However, the additional disability-related costs of a holiday — such as extra support worker hours while travelling — can be funded if the holiday supports your goals (e.g., "maintaining social connections by visiting family interstate"). The flights and accommodation? No. The support worker to make the trip possible? Possibly yes.

How to Argue Your NDIS Support Is Reasonable and Necessary: A 5-Step Template

When requesting funding — whether in a planning meeting, a review, or an appeal — structure your argument around the six criteria. Here's a template:

1. Name the support — what are you asking for, specifically?
2. State your goal — which goal in your plan does this support help you achieve?
3. Walk through the criteria — explain, for each of the six, why this support passes. Use specific language: "This support is related to my disability because…" "It represents value for money because…"
4. Provide evidence — a letter from your occupational therapist, physio, or specialist saying the support is necessary carries enormous weight. The NDIA almost never overrides a treating professional's recommendation without strong counter-evidence.
5. Address alternatives — anticipate the NDIA's objections. What's the cheaper alternative, and why isn't it suitable? Why can't informal supports fill this gap? Head off the pushback before it comes.

What the AAT Says About NDIS Reasonable and Necessary: Key Tribunal Decisions

The Administrative Appeals Tribunal (AAT) has issued dozens of decisions interpreting "reasonable and necessary." Some key principles that have emerged:

• "Reasonable" doesn't mean "cheapest." The AAT has repeatedly found that the NDIA must fund supports that are effective, even if a cheaper option exists — as long as the cost is not disproportionate to the benefit.
• Informal supports must be sustainable. The AAT has pushed back against the NDIA's tendency to assume family can provide unlimited support indefinitely. Carer burnout and ageing parents are legitimate reasons to increase formal supports.
• Early intervention is taken seriously. The AAT has upheld funding for supports that prevent deterioration, even when the immediate benefit is hard to quantify, because the long-term cost of deterioration is higher.

If the NDIA denies your request, and the denial doesn't align with AAT precedent, you have strong grounds for review. Learn what's been decided before — it's the best evidence you have. For the full process of challenging NDIA decisions, read our NDIS complaints and appeals guide.