Pre-existing conditions and health insurance: how the 12-month rule works

What is a pre-existing condition in health insurance?

In Australian private health insurance, a pre-existing condition is an ailment, illness or condition whose signs or symptoms existed at any time in the 6 months ending on the day you became insured under the policy. The definition is in section 75-15 of the Private Health Insurance Act 2007, read on the Federal Register of Legislation on 8 November 2026 (Compilation No. 42, compilation date 19 September 2026).

Three parts of that definition do most of the work:

• It is an opinion, not a diagnosis. The Commonwealth Ombudsman’s factsheet says the test “relies on the presence of signs or symptoms”, and that nobody needs to have known what the condition was.
• The opinion belongs to the insurer’s doctor. Section 75-15 gives the call to a medical practitioner the insurer appoints, who must have regard to what your treating doctor provides.
• The clock follows the policy. The 6 months run back from the day you joined, or from the day you upgraded for the added benefits. Section 75-15(3) adds a rule few people know: if your insurer closes your product and moves you to a replacement, the look-back still runs from the date you joined the old product, not the replacement.

“Pre-existing ailment” on a fund’s form means the same thing. The law uses one test for all three words.

How does the 12-month pre-existing condition rule work?

Section 75-1 of the Private Health Insurance Act 2007 sets the longest waiting period an Australian insurer may apply to hospital treatment and hospital-substitute treatment. The figures below were read in Compilation No. 42 on 8 November 2026, and PrivateHealth.gov.au and the Department of Health, Disability and Ageing state the same maximums.

Last verified 8 November 2026.

The 12 months is a ceiling, and it runs continuously from the join or upgrade date. The Ombudsman’s factsheet says that once a member has held the hospital policy for a continuous 12 months, the pre-existing condition waiting period “no longer applies”. Treatment received during the wait cannot be claimed later just because the wait has ended.

Waivers of this 12-month wait are rare. The Ombudsman’s brochure says insurers very rarely waive the 12-month pre-existing wait, so the promotions people see for waived waiting periods are almost always on extras. Which waits funds were actually waiving is set out in health insurance with no waiting period.

Can you get health insurance with a pre-existing condition?

Yes, at the same price as anyone else. Section 55-5 of the Private Health Insurance Act 2007 sets out the principle of community rating, and it bars an Australian insurer from “improperly discriminating” on the basis of a person’s chronic disease, illness or medical condition, or the frequency with which a person needs hospital treatment. Read in Compilation No. 42 on 8 November 2026.

In practice that means three things in 2026–27:

• An insurer cannot refuse to sell you a complying hospital or extras policy because of your health.
• It cannot charge you a higher premium because of your health. PrivateHealth.gov.au says insurers must let you buy any type of cover “at the same price as any other person”.
• It cannot exclude the condition permanently. The only lever the law gives an insurer is the waiting period of up to 12 months.

Age is treated differently. Section 55-5 carves out the Lifetime Health Cover loading and the age-based discount, so those can change what you pay. Neither depends on your health. The Lifetime Health Cover loading guide has the arithmetic. None of this is personal advice, and it does not take your health or finances into account.

Is there a list of pre-existing conditions?

No, and the Commonwealth Ombudsman says there cannot be one. Its factsheet, read on 8 November 2026, states that whether a member has a pre-existing condition must be assessed against that person’s own circumstances, and that “it is not allowable to say that certain conditions are always pre-existing”.

The Ombudsman sets out the tests an insurer’s doctor has to apply to each case in Australia:

• there must be a direct link between the condition needing hospital treatment and the signs or symptoms in the 6 months before joining or upgrading
• the signs or symptoms must have been reasonably apparent to you, or to a reasonable general practitioner had you been examined in that period
• risk factors, including family history, are not signs or symptoms

The Ombudsman’s brochure gives a worked case. Pam had nausea and abdominal pain one month before she took out hospital cover. Shortly after joining, a specialist diagnosed gallstones and recommended surgery. The insurer’s doctor found the symptoms existed in the 6 months before she joined, so the 12-month wait applied, even though her GP had not named gallstones at the time.

So asthma, diabetes or a bad knee are not automatically pre-existing. Each one is pre-existing only if the evidence shows signs or symptoms in that person’s 6-month window.

Who decides whether a condition is pre-existing, and how?

A medical practitioner appointed by the insurer decides, under section 75-15 of the Private Health Insurance Act 2007. Your GP and specialist supply the evidence; they do not make the call. Section 75-15(2) requires the appointed practitioner to have regard to any information the treating doctor gives.

The Commonwealth Ombudsman’s waiting periods brochure, read on 8 November 2026, describes what an Australian insurer should do when a member inside the first 12 months asks about a hospital admission:

1. Give general information about the pre-existing condition rule. At this stage it cannot say whether your condition is pre-existing.
2. Send forms for your GP and specialist to complete and return. Funds usually call this a pre-existing condition certificate.
3. Contact you within 5 working days of receiving that information. If it has not, the Ombudsman says to ring the insurer and ask whether it has decided.

The forms ask your doctors when symptoms first appeared, so the dates in your medical record matter more than anything you remember. A planned procedure is the case to start this early: the insurer needs time, and the brochure warns that an urgent admission may go ahead before it has decided. Asking the insurer to confirm its decision in writing, with the condition named, is the record the Ombudsman will later ask to see.

What happens if you go into hospital before the fund decides?

You carry the risk. The Commonwealth Ombudsman’s brochure, read on 8 November 2026, says that if you proceed with an admission before the insurer has told you whether you are entitled to benefits, “you may become responsible for all costs associated with the admission”. This is the mistake behind many complaints: people treat silence as a yes.

If the insurer’s doctor later finds the condition was pre-existing, the hospital account, the surgeon, the anaesthetist and any prosthesis are yours to pay as a private patient. The insurer pays nothing for that admission, and an excess you thought you were paying does not change that.

People in this position in Australia usually weigh up three options:

• Wait for the decision, if their doctor says delay is medically safe.
• Go public. The Ombudsman’s factsheet says members with a pre-existing condition can still be treated in a public hospital under Medicare, as a public patient on the hospital’s timetable. The public vs private hospital guide sets out the 2024–25 elective surgery waits.
• Wait out the 12 months, after which the condition is covered at the policy’s level.

The Ombudsman’s brochure says the treating doctor is best placed to say whether delay is medically advisable. This is general information, not medical or financial advice.

What does a 12-month pre-existing wait cost in premiums?

The premium is payable from the first day, and the Australian Government Rebate reduces it by a percentage that depends on income and age. The table converts that percentage into dollars for 12 months of premiums on two hospital policies listed on PrivateHealth.gov.au on 8 November 2026, both single cover in NSW and the ACT: Bupa Silver Plus Essential Hospital $500 Excess at A$186.10 a month, and Peoplecare Bronze Plus Hospital $750 at A$140.71 a month. These are worked examples, not a recommendation. PrivateHealth.gov.au does not state the period a listed premium applies to, so both are dated by the day they were read.

Rebate rates and thresholds from the ATO, read 8 November 2026. Last verified 8 November 2026.

For comparison, the 2025–26 rates that applied from 1 July 2025 to 31 March 2026 were 24.288%, 16.192% and 8.095% for a single under 65, with tier thresholds of A$101,000, A$118,000 and A$158,000. On the Silver Plus premium the base-tier rebate would have been A$542.40 a year at the 2025–26 rate against A$538.60 now.

A 12-month wait that starts on 1 December 2026 crosses the 1 April 2027 premium round and the rebate rate change on the same date. Neither the new premiums nor the new rate were published on 8 November 2026, so the figures above hold today’s prices constant.

Worked example: a knee that started hurting before the policy did

Sam is 52, lives in Sydney, earns A$98,000 a year and is single. Her right knee began aching in September 2026. She joins the Bupa Silver Plus Essential Hospital $500 Excess policy on 1 December 2026 at the A$186.10 a month listed on PrivateHealth.gov.au on 8 November 2026. In March 2027 a specialist recommends a knee arthroscopy.

• Look-back window: 1 June 2026 to 1 December 2026. The September ache sits inside it.
• Assessment: her GP and specialist complete the insurer’s forms. If the insurer’s doctor finds the knee symptoms existed in the window, the condition is pre-existing.
• Wait ends: 1 December 2027, 12 months after joining (section 75-1 of the Private Health Insurance Act 2007).
• Premiums paid by 1 December 2027: A$186.10 × 12 = A$2,233.20. At the base-tier rebate of 24.118% for income of A$105,000 or less in 2026–27, the rebate is A$538.60, so Sam pays A$1,694.60 net, holding the price constant.
• If she has the arthroscopy privately in March 2027: the insurer pays nothing toward it, and she pays the full private bills herself.

If the knee symptoms had begun in April 2026, outside the window, the condition would not be pre-existing, and the usual 2-month hospital wait would end on 1 February 2027. Same knee, same policy, 10 months’ difference, decided by the date in a GP’s notes. The arithmetic is Plain Cover’s, from the figures shown.

Why fertility treatment and IVF cause so many pre-existing disputes

Infertility is the case the Commonwealth Ombudsman singled out in Quarterly Update 117, covering 1 January to 31 March 2026. The Ombudsman wrote that a person may not know they have a fertility issue when they take out cover, and may find out only when they start trying for a child or seek treatment such as IVF.

The Ombudsman’s point is that infertility as a medical idea and the pre-existing condition test in Australian law “are not necessarily the same thing”. Needing fertility treatment does not on its own make a condition pre-existing. The question is still whether the insurer’s doctor finds signs or symptoms of a specific condition in the 6 months before joining or upgrading.

The update flags two groups for whom this is hardest to follow: same-sex couples and people seeking a child without a partner, who may need treatment with no diagnosed fertility condition at all. For them a pre-existing finding can be hard to reconcile with their own situation. The Ombudsman’s view is that the complaint is often less about whether a wait applies than about whether the person understands what was assessed and which condition the decision relates to.

PrivateHealth.gov.au lists IVF under the assisted reproductive services clinical category, read 8 November 2026, so this question arises only on a hospital policy that includes that category. A written decision naming the condition assessed is the document to ask for.

How often are pre-existing condition decisions disputed?

Pre-existing conditions are one of the largest single complaint issues the Commonwealth Ombudsman handles. In the 2024–25 annual summary in Quarterly Update 114, the Ombudsman reported 317 pre-existing condition complaints, up from 294 in 2023–24, out of 3,411 complaints of every kind in 2024–25. That is 9.3%. The counts below come from Updates 114 and 117, read on 8 November 2026.

Changes are Plain Cover arithmetic. Last verified 8 November 2026. As at that date the Ombudsman’s industry updates page listed Update 117 as the latest, so no April to June 2026 count exists to quote. Update 117 also notes a new complaints system from May 2026 and warns that some figures may differ from earlier reports.

How the Ombudsman handles one: with your written consent it requests the insurer’s medical report and the certificates your doctors completed, then explains the decision, investigates, or negotiates with the insurer. It checks compliance with the Pre-Existing Condition Best Practice Guidelines, released in September 2001, and where they were not followed it may negotiate a reduced hospital account. Complaints go to the Ombudsman on 1300 362 072, after first raising the decision with the insurer.

Does the 12-month rule restart when you switch or upgrade?

On a switch at the same or a lower level of hospital cover in Australia, no. Section 78-1(2) of the Private Health Insurance Act 2007 limits the new insurer to the unexpired balance of any waiting period you were serving, so months already served carry across. The detail, including clearance certificates, is in do you re-serve waiting periods when you switch.

The transfer has to count as a transfer. Section 75-10 treats you as transferring if you join the new policy while still on the old one, or within 7 days of leaving it, or within a longer gap the new insurer allows, and your old premiums were paid up. Miss that window and the new insurer can treat you as a new member, with a fresh 6-month look-back and a fresh 12-month wait. Read on 8 November 2026.

On an upgrade, the rule restarts for the added benefits only. The Ombudsman’s brochure says that during the 12 months after moving to a higher level, a pre-existing condition attracts only the lower benefits of the previous cover. Adding a clinical category, such as moving from Bronze Plus to Silver Plus to pick up a category your old policy excluded, is the common trigger. The tiers compared guide lists which categories each tier must include.