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Australia’s largest-ever class action settlement isn’t a bushfire case or a bank dispute anymore. It’s Robodebt. Between the original 2021 settlement and a further AU$548.5 million approved by the Federal Court in June 2026, the Commonwealth has now paid out more than AU$1.7 billion to people wrongly pursued under the failed debt recovery scheme.
That record has changed hands before, and it’ll likely change again. Below is an updated look at the biggest class actions in Australia and around the world, what happened in each one, and how they differ from the individual compensation claims most people are actually eligible to bring.
Case Overviews
- Australia’s biggest class action is Robodebt: AU$1.2 billion in 2021, plus a further AU$548.5 million (including AU$475 million in compensation to roughly 125,000 people) approved in June 2026.
- The world’s biggest securities fraud class action remains the 2008 Enron settlement, worth US$7.2 billion (around AU$10 billion at today’s exchange rate).
- Recent Australian class actions cover superannuation fees, the Optus and Medibank data breaches, and Qantas flight credits.
- A class action needs hundreds or thousands of people with the same claim against the same defendant. Most personal injury, medical negligence and product liability matters don’t meet that bar, and are run as individual claims instead.
- If you’ve been affected by a defective medical device, medication or negligent treatment, but there’s no class action open, you can usually still bring your own compensation claim.
A Brief History of Class Actions
Representative litigation is older than most people assume. English Chancery courts allowed a “bill of peace” (one case standing in for many identical disputes) as far back as the 1700s. The idea was formalised in the United States through Federal Equity Rule 48 in 1842, which allowed a small group to sue or be sued on behalf of a larger class that was too large for all to appear in court.
That rule evolved into Federal Rule of Civil Procedure 23, adopted in 1966, which is still the basis of the modern US class action system.
Australia came to the party much later. The Federal Court of Australia only gained the power to hear representative proceedings in 1992, under Part IVA of the Federal Court of Australia Act 1976. Victoria followed in 2000, introducing its own group proceedings regime under Part 4A of the Supreme Court Act 1986, which is a big part of why so many of the cases below, including Robodebt and the Black Saturday litigation, ended up in Victorian courts.
The World’s 10 Biggest Class Action Settlements
The biggest class actions in history are almost all securities fraud cases, where shareholders sue a company for misleading the market. According to the Stanford Securities Class Action Clearinghouse, which tracks every US securities settlement on record, the ten largest are:
| Rank | Case | Settlement | Year |
| 1 | Enron Corporation | US$7.23 billion | 2008 |
| 2 | WorldCom, Inc. | US$6.13 billion | 2005 |
| 3 | Tyco International Ltd. | US$3.2 billion | 2013 |
| 4 | Cendant Corporation | US$3.19 billion | 2010 |
| 5 | Petrobras (ADR holders) | US$3 billion | 2018 |
| 6 | Nortel Networks Corporation | US$2.94 billion | 2007 |
| 7 | AOL Time Warner, Inc. | US$2.5 billion | 2006 |
| 8 | Bank of America Corp (Merrill Lynch merger) | US$2.43 billion | 2013 |
| 9 | Household International, Inc. | US$1.58 billion | 2016 |
| 10 | Valeant Pharmaceuticals International | US$1.21 billion | 2021 |
(Source:Stanford Securities Class Action Clearinghouse)
Outside securities fraud, a handful of other settlements dwarf even Enron. BP’s Deepwater Horizon oil spill settlement has cost the company roughly US$20 billion across its economic, medical and government components since 2012. Volkswagen agreed to pay up to US$14.7 billion to resolve its diesel emissions scandal in 2016. And the Purdue Pharma and Sackler family opioid settlement, worth US$7.4 billion, only came into effect in 2026 after years of bankruptcy court proceedings.
The Biggest Class Actions in Australia
Australia’s numbers are smaller, but the cases matter just as much to the people involved. Here’s how the record has shifted over the past 15 years.
Robodebt (2021 and 2026)
The Commonwealth’s automated debt recovery scheme wrongly pursued hundreds of thousands of welfare recipients between 2015 and 2019. A 2021 settlement was worth around AU$1.2 billion, but the Full Federal Court later found it had short-changed victims because it didn’t reflect what the Robodebt Royal Commission uncovered. In June 2026, the Federal Court approved a further AU$548.5 million, making Robodebt Australia’s biggest class action settlement on record.
Black Saturday Bushfires (2014–2015)
Before Robodebt, this was the record-holder. The Kilmore East–Kinglake action settled for AU$494.67 million, and the Murrindindi (Marysville) action for AU$300 million. A combined AU$794.67 million, of which AU$698.5 million was distributed to survivors after legal and administration costs.
Bank Fees Class Actions (2010–2016)
Hundreds of thousands of customers joined a long-running campaign against the major banks over late-payment and overdrawn-account fees. It ended in the banks’ favour: in Paciocco v ANZ (2016), the High Court found ANZ’s late payment fees weren’t unenforceable penalties once the bank’s full costs were taken into account, effectively closing off most of the remaining claims.
Superannuation Fee Class Actions (2020)
Colonial First State and the Commonwealth Bank settled for a record AU$249 million over claims that members were kept in low-interest cash options that benefited the bank. AMP settled a similar case for AU$120 million.
Qantas Flight Credits (2026)
Qantas agreed to pay AU$105 million after customers claimed the airline made it unreasonably difficult to redeem COVID-19 flight credits, one of the more consumer-focused class actions to settle this year.
Sigma Pharmaceuticals (2011)
One of Australia’s earliest large shareholder class actions was settled for AU$57.5 million after the company issued misleading profit guidance.
Optus and Medibank Data Breaches (Ongoing)
Both insurers and telcos are still defending class actions over the 2022 cyberattacks that exposed millions of Australians’ personal information. The Optus matter, along with a related regulatory case, isn’t listed for a hearing until 2027, and Medibank’s proceeding is still before the Supreme Court of Victoria. Whichever way these go, they’re worth watching. A loss for either company could easily produce Australia’s next record settlement.
The Record Won’t Stay Put For Long
Ten years ago, this list was topped by a bushfire. Now it’s a government IT failure, and the next entry could just as easily be a data breach or a defective product recall. What hasn’t changed is the underlying idea: when enough people are harmed by the same conduct, the law lets them act together rather than fighting the same battle one at a time.
If you’re not part of a class action but you’ve still been hurt by someone else’s negligence, that principle still applies to you, just on an individual footing, with your own timeline and your own outcome.
Class Action or Individual Claim?
We don’t run class actions at Henry Carus + Associates, but a lot of the same events that make headlines as class actions also give rise to claims that individuals can bring on their own, without needing hundreds of other people to sign up first.
If you’ve had a hip replacement recall, used a Mirena IUD, received breast implants, taken Depo Provera, or been exposed to PFAS contamination, you may have grounds for a claim even where no class action is running, or you’d rather not wait years for one to resolve. That’s the kind of matter ourdefective product claims andmedical negligence lawyers handle every week, as well as in the broader field ofpersonal injury law.
Every case is different, and there’s no cost to finding out where you stand. Get in touch with ourcompensation claim lawyers for an obligation-free chat about your situation.
