Since 21 March 2026, section 4.55(1) of the Environmental Planning and Assessment Act 1979 covers more than errors and misdescriptions. It now includes any modification of a development consent that has no environmental impact, and the council must determine those applications within 14 calendar days of lodgement. The change came from the Planning System Reforms Act 2025, with a new section 4.55A and section 118A of the EP&A Regulation 2021. If a section 4.55(1) application is not determined in time it cannot be refused; the Department describes this as a 14-day deemed approval mechanism. There is no notification and no change to the fee. For builders and developers managing approved houses, duplexes and townhouses, it creates a faster lane for genuinely neutral changes. Anything with even a minimal impact still goes through section 4.55(1A) or 4.55(2).
Key takeaways
- Section 4.55(1) now covers modifications that correct minor errors, misdescriptions or miscalculations and any modification with no environmental impact; minimal impact changes moved out to section 4.55(1A).
- Section 4.55(1) applications must be determined within 14 calendar days from lodgement (the day after the fee is paid), and requests for more information do not stop the clock.
- An application not determined within 14 days cannot be refused, but the council can still impose conditions that are not inconsistent with the modification sought.
- Section 4.55(1) applications do not need notification, the fee has not increased, and the pathway is non-reviewable.
- The changes apply to modification applications lodged from 21 March 2026, whenever the original DA was approved.
Who this is for: builders, developers and owner builders with an approved DA in Sydney or regional NSW who need to make changes during design development or construction, and want to choose the right modification pathway under the rules in force since March 2026.
What changed on 21 March 2026?
The Department of Planning, Housing and Infrastructure’s information sheet on the second commencement of the Planning System Reforms Act 2025 explains the changes:
- modifications with no environmental impact shifted from section 4.55(1A) to section 4.55(1);
- a 14 day period to determine section 4.55(1) modifications was introduced in new section 118A of the EP&A Regulation 2021;
- modifications not determined within 14 days cannot be refused and can only be approved with conditions that give effect to the modification (new section 4.55A);
- when assessing modifications under sections 4.55(1A), 4.55(2) or 4.56, the section 4.15(1) matters are considered only to the extent they are relevant to the modification.
The Department’s FAQ on the second proclamation adds the practical detail. The 14 days are calendar days, extended to the next business day if the last day falls on a weekend or public holiday. The clock starts at lodgement, which is the day after the fee is paid. Councils can ask for more information, but that does not stop the clock, and if critical information is not provided the council can refuse within the 14 days. Councils are encouraged to check within 7 days of submission whether an application is likely to meet the section 4.55(1) test, and to point applicants to another pathway if not.
Which modifications have no environmental impact?
That is now the key question, and it is a judgment the council makes. The FAQ is clear that if, during assessment, the council forms the view that the change would have an environmental impact, it keeps full discretion to refuse the application, and the applicant may need to lodge again under section 4.55(1A) or 4.55(2). As a guide only, these are the kinds of changes that are likely and unlikely to qualify:
| Change | Likely pathway |
|---|---|
| Correcting a wrong lot number, address or drawing reference in the consent | 4.55(1), minor error or misdescription |
| Internal layout changes wholly within the approved envelope, no change to windows, floor area or use | Possibly 4.55(1), no environmental impact |
| Changing a condition’s timing (for example, when a report must be provided) without changing what it requires | Possibly 4.55(1) |
| Swapping an approved external material for a similar one | Depends on the council’s view; may be 4.55(1A) |
| Moving or enlarging windows facing a neighbour | 4.55(1A) or 4.55(2): privacy impact |
| Small increase in floor area or height | 4.55(1A) or 4.55(2) |
| Changing the driveway, parking or stormwater design | 4.55(1A) or 4.55(2) |
| Changing a housing and productivity contribution condition | The 14 day timeframe does not apply unless the change has the Minister’s approval |
The honest test is whether anyone outside the site, or any planning control, is affected at all. If the answer is “a little”, the change belongs in section 4.55(1A).
How do the modification pathways compare now?
| Pathway | Scope | Notification | Timeframe |
|---|---|---|---|
| 4.55(1) | Minor errors, misdescriptions, miscalculations, and modifications with no environmental impact | Not required | 14 calendar days; cannot be refused after that |
| 4.55(1A) | Modifications of minimal environmental impact, substantially the same development | As the council’s community participation plan requires | Ordinary assessment period |
| 4.55(2) | Other modifications, substantially the same development | Usually notified | Ordinary assessment period |
| New DA | Changes that are no longer substantially the same development | Notified as a DA | Full DA assessment |
If a 4.55(1A) or 4.55(2) application is refused, the review rules that took effect on 21 March 2026 apply: a review can be lodged within 6 months (the old 28 day limit for modification reviews is gone), and where council staff made the decision, the applicant can elect to have the local planning panel determine the review. Section 4.55(1) itself is described by the Department as non-reviewable.
How to use the new pathway well
- Describe the change precisely and show it is neutral: compare approved and proposed plans with the change clouded.
- Explain in a short statement why there is no environmental impact: no change to envelope, floor area, openings facing neighbours, landscaping, parking or stormwater.
- Check the consent conditions the change touches, and propose amended wording.
- Lodge with complete information, because a request for more information does not stop the clock and an incomplete application is likely to be refused.
- If the council indicates within the first week that the change is not eligible, switch to 4.55(1A) rather than wait for a refusal.
- Do not start the modified work until the modified consent issues. A certifier cannot certify work that is inconsistent with the consent.
Where this pathway will trip people up
The main risk is optimism. Labelling a change “no environmental impact” does not make it so, and a refusal costs the 14 days plus the time to re-lodge in the right pathway. The second risk is bundling: one neutral internal change and one window relocation in the same application. The window takes the whole application out of section 4.55(1). Lodge them separately if the neutral change is time-critical. The third is construction already under way. Builders sometimes make “small” changes on site and seek approval afterwards. A modification can only approve work going forward, and work built inconsistently with the consent is unauthorised until it is regularised.
Definitions
- Section 4.55(1) modification
- A modification to correct a minor error, misdescription or miscalculation, or since 21 March 2026 any modification with no environmental impact, determined within 14 calendar days.
- Section 4.55(1A) modification
- A modification involving minimal environmental impact where the development remains substantially the same.
- Section 4.55(2) modification
- Any other modification where the development remains substantially the same development as originally approved.
- Section 4.55A
- The provision, in force from 21 March 2026, under which a section 4.55(1) application not determined within 14 days cannot be refused.
- Substantially the same development
- The threshold every modification must meet; changes beyond it need a new DA.
Frequently asked questions
How long does council have to decide a section 4.55(1) modification?
14 calendar days from lodgement, for applications lodged from 21 March 2026. If not determined in time, the application cannot be refused, although conditions consistent with the modification can still be imposed.
Does a section 4.55(1) modification get notified to neighbours?
No. The Department’s FAQ confirms section 4.55(1) applications do not require notification.
Can I use section 4.55(1) for a consent approved before 2026?
Yes. The new rules apply to modification applications lodged from 21 March 2026, regardless of when the DA was approved.
What if the council thinks my change does have an impact?
It can refuse the section 4.55(1) application, and you would need to lodge under section 4.55(1A) or 4.55(2) with the information needed to assess the impact.
We prepare modification applications under every pathway, and choose the pathway carefully so that the 14 day lane is used only where it will succeed, through our DA modifications and RFI responses service. If your approved house, duplex or townhouse project needs changes, request a fee proposal.
Sources and references
- NSW Department of Planning, Housing and Infrastructure, Information sheet: Second commencement of the Planning System Reforms Act 2025, accessed October 2026
- NSW Department of Planning, Housing and Infrastructure, Planning System Reforms second proclamation FAQ (March 2026), accessed October 2026
- Environmental Planning and Assessment Act 1979, sections 4.55, 4.55A and 4.56, accessed October 2026
- Environmental Planning and Assessment Regulation 2021, section 118A, accessed October 2026
Information disclaimer. This article is general planning information prepared by the URBA Planning Team and is current at the date of publication. It is not planning, legal or financial advice for any specific property. Planning instruments, development control plans, state policies and the National Construction Code are amended regularly and councils interpret them differently; the controls quoted here should be confirmed against the versions in force at the date of lodgement and against the consent authority’s current requirements. Reliance on this article is at the reader’s own risk. URBA Planning, a division of Contrive Consultants Pty Ltd, accepts no liability for loss arising from its use. For advice on a specific site, contact URBA for a fee proposal.