ASSA 5010 is the Australian standard that sets out which parts of a company’s climate report must be checked by an auditor, and how closely it works alongside ASSA 5000. This governs how that checking is done, and both sit under the mandatory climate reporting rules in the Corporations Act.
This matters now because Group 2 companies began their first reporting period on 1 July 2026. This article explains what ASSA 5010 requires, who it applies to, and when limited assurance steps up to reasonable assurance.
Key takeaways
- In your first year, only governance, part of your strategy disclosures, and your Scope 1 and 2 emissions need limited assurance.
- Your scenario analysis, transition plan, risk management and targets are all required in that report. No assurance is needed on them, though auditors will still review those sections.
- Reasonable assurance starts in your fourth reporting year. For Group 2, that is the year commencing 1 July 2029.
What is ASSA 5010?
ASSA 5010 is a timetable. The Auditing and Assurance Standards Board made it under the Corporations Act, and it covers reporting years commencing 1 January 2025 to 30 June 2030.
| Group | Year 1 | Year 2 | Year 3 | Year 4+ |
|---|---|---|---|---|
| Group 1 | 1 Jan 2025 to 30 Jun 2026 | 1 Jul 2026 to 30 Jun 2027 | 1 Jul 2027 to 30 Jun 2028 | From 1 Jul 2028 |
| Group 2 | 1 Jul 2026 to 30 Jun 2027 | 1 Jul 2027 to 30 Jun 2028 | 1 Jul 2028 to 30 Jun 2029 | From 1 Jul 2029 |
| Group 3 | 1 Jul 2027 to 30 Jun 2028 | 1 Jul 2028 to 30 Jun 2029 | 1 Jul 2029 to 30 Jun 2030 | From 1 Jul 2030 |
Each cell is the window your financial year has to start in, so find your group’s row and the year you are in.
Assurance itself is not new. Our explainer on climate and nature assurance covers why investors and lenders were already asking for it before the rules made it mandatory.
Limited assurance vs reasonable assurance, what’s the difference?
There are two levels of checking, and the difference is how hard the auditor looks.
ASSA 5010 calls them review and audit, because that’s the language in the Corporations Act. Your engagement letter will probably say limited assurance and reasonable assurance. They are the same two things.
| Limited assurance (review) | Reasonable assurance (audit) | |
|---|---|---|
| What the auditor does | Asks questions and runs checks over your numbers | Tests the systems behind the numbers, samples more of them, may visit sites. |
What they conclude | Nothing came to our attention to suggest it is wrong (a negative conclusion) | It is fairly presented in all material respects (a positive conclusion) |
Does ASSA 5010 apply to your business?
It applies if you lodge financial reports under Chapter 2M of the Corporations Act and are large enough to need a sustainability report alongside them.
Size thresholds sort businesses into three groups, and your group sets your start date. Group 1 began with reporting years commencing 1 January 2025. Group 2 followed from 1 July 2026, and Group 3 starts from 1 July 2027.
After that, everything depends on which reporting year you are in. That is what decides which disclosures need assurance, and at what level. Our guide to ASRS climate reporting sets out the thresholds, and our mandatory climate reporting service helps first-time reporters work out what is enough.
What ASSA 5010 requires in your first year of reporting
In your first year, three areas need limited assurance.
- Governance: Who oversees climate risk and how, under paragraph 6 of AASB S2.
- Strategy: The climate risks and opportunities you have identified, limited to subparagraphs 9(a), 10(a) and 10(b).
- Emissions: Your Scope 1 and Scope 2 figures.
Our article on the governance gap in risk management goes deeper on the first of those.
Four more disclosures are required in your first report. No assurance is needed on them, though auditors will still review those sections.
- Climate resilience and scenario analysis
- Transition plans
- Risk management
- Metrics and targets
Scope 3 sits outside both lists, with transition relief applying for the first year of reporting.
So does anyone check those sections?
Your auditor will read them, but no assurance conclusion is required over them. They also go into your report under a directors’ declaration, which is a formal statement from your board, and ASIC can still look at them.
You can pay to have them checked anyway. Whether that’s worth it in year one depends on how your scenario analysis and transition plan would read to an outsider. Our piece on director personal liability covers what’s at stake.
When does reasonable assurance apply to your business?
Years two and three stay at limited assurance, with everything in scope by then. From your fourth year, your whole report moves up to reasonable assurance. For Group 2, that is the year commencing 1 July 2029.
| Disclosure | Year 1 | Year 2 and 3 | Year 4+ |
|---|---|---|---|
| Governance | Limited | Limited | Reasonable |
| Strategy: risks and opportunities | Limited | Limited | Reasonable |
| Climate resilience and scenario analysis | None | Limited | Reasonable |
| Transition plans | None | Limited | Reasonable |
| Risk management | None | Limited | Reasonable |
| Scope 1 and 2 emissions | Limited | Limited | Reasonable |
| Scope 3 emissions | Not Applicable | Limited | Reasonable |
| Metrics and targets | None | Limited | Reasonable |
So what about the 2030 date?
That date is the backstop in the Corporations Act, which requires sustainability reports for years commencing on or after 1 July 2030 to be audited. It applies to every entity. For Group 1 and Group 2, the fourth reporting year arrives sooner, from 1 July 2028 and 1 July 2029, so reasonable assurance starts before the backstop takes effect. Watch the wording too: these apply to years commencing on or after those dates, not years ending.
Could any of this still change?
Two things are open. The May 2026 Federal Budget flagged consultation on adjusting assurance settings, covered in our summary of what the Budget changed for ASRS reporting. The AUASB is also weighing whether assurance should cover the directors’ declaration in Group 2’s first year. Neither has moved the start dates or the 2030 end point.
How to prepare for sustainability assurance
Work backwards from what’s in scope. Your assurer will ask for three evidence trails.
- Governance: Board papers showing who holds climate risk and when it was discussed.
- Strategy: How you arrived at the risks and opportunities you identified.
- Scope 1 and 2: Activity data, the emission factors you used, and a clear line from source document to reported figure.
Build these in year one even though only part of your report needs assurance. Your assurer forms a view of your systems now, and a tidy first year buys you a cheaper fourth.
Your next steps
The 2030 date is worth fixing first. If your planning is built around it, ASSA 5010 gives you a year less than you think.
- See how year one played out: What Australia’s first reporters learned.
- Find out where you stand: Our ASRS readiness workshop gives you a readiness snapshot and a gap-aligned roadmap.
- Decide what to assure voluntarily: Our climate and nature assurance team works through that call with first-year reporters.
Frequently Asked Questions
ASSA 5000 sets out how a sustainability assurance engagement is performed. ASSA 5010 answers which parts of your report must be reviewed or audited, and in which year.
Transition relief applies in the first year of reporting, so there is nothing to assure. It moves to limited assurance from your second year.
Only to the level they were assured last year. If information was not assured last year, its comparative needs no assurance now, and AASB S2 requires no comparatives at all in your first reporting period.
Not in year one. The AUASB is considering whether it should be covered for years commencing 1 July 2026 to 31 December 2027, which affects Group 2 first reporters.
References
Auditing and Assurance Standards Board: ASSA 5010 Timeline for Audits and Reviews of Information in Sustainability Reports
Auditing and Assurance Standards Board: Sustainability Assurance
