Duplicate Images Are Flooding Sydney's Digital Planning Records — And Other Global Cities Are Already Ahead

Sydney's planning system has a quiet but costly problem buried inside thousands of development application portals: duplicate images. The same site photograph submitted under multiple file names, scanned heritage documents re-uploaded in triplicate, drone imagery pasted into PDF sets alongside lower-resolution copies of the same shot. Across at least a dozen NSW councils, digital records management teams are flagging the issue as a growing drag on assessment times and storage costs.

The timing matters. The NSW government is under intense pressure to accelerate housing approvals — Premier Chris Minns has made planning reform a central plank of his government's agenda — and any inefficiency in the DA pipeline draws scrutiny. Duplicate image files are not a glamorous problem, but planning officers at councils including the City of Sydney and Cumberland City Council have described the problem in public submissions to the NSW Department of Planning as a contributor to administrative bottlenecks. The issue is especially acute in Western Sydney, where the volume of DAs lodged for the Aerotropolis precinct around Badgerys Creek has surged since 2024.

What Sydney Is Doing — and What It Isn't

The NSW Planning Portal, which processes electronic DAs statewide, does not currently apply automated duplicate-image detection at the point of lodgement. Files are accepted and stored as submitted, leaving councils to manually audit packages after the fact. The City of Sydney's records management team began a de-duplication audit of its DA image archive in late 2025, focusing on the Redfern-Waterloo corridor where urban renewal submissions have been particularly dense. Cumberland City Council, covering suburbs from Merrylands to Auburn, flagged in its 2025–26 operational plan that digital records storage costs had increased, partly due to redundant file accumulation.

Compare that to Amsterdam, where the municipal planning authority integrated perceptual hash-based image comparison into its Omgevingsloket (environment desk) system in 2023. The tool flags near-identical images before a file is formally accepted, prompting the applicant to review and consolidate. Singapore's Urban Redevelopment Authority went further, embedding AI-assisted deduplication into its GoBusiness Licensing portal as part of a 2024 upgrade, reducing average DA file sizes by a measurable margin according to URA's published annual report. Neither city built the tools from scratch — both drew on open-source libraries already used in e-commerce and social media content moderation.

London's 32 borough councils remain fragmented, much like NSW's 128 councils, and the picture there is similarly uneven. The City of London Corporation and Tower Hamlets both use Idox software, which includes basic duplication flags, but outer boroughs often do not. Toronto, by contrast, standardised its Development Applications system across all city divisions in 2022 and included image hash-checking as a baseline requirement from day one.

The Cost of Doing Nothing

Storage is cheap, but assessment officer time is not. The average fully-loaded cost of a council planning officer in metropolitan Sydney was estimated at between $110,000 and $130,000 per year in 2025, according to LGNSW workforce data. If officers across a large council spend even two hours per week sorting through redundant image files, the annual cost across a team of 20 planners runs into six figures — money that could fund additional assessment capacity.

The NSW Department of Planning launched its Digital Planning Strategy in 2023 with a commitment to continuous improvement of the Planning Portal. The strategy's third iteration, expected to be released in the second half of 2026, is understood to include provisions for file validation at lodgement — though whether that will extend to image-level deduplication has not been confirmed publicly.

For councils waiting on a state-level fix, the practical path is straightforward. Open-source tools such as ImageHash, already deployed by several federal government agencies, can be integrated with existing document management systems without significant licensing cost. The City of Melbourne quietly added a similar layer to its ePlanning portal in March 2025. Sydney's councils do not need to wait for Macquarie Street to move. The technology exists, the use cases are proven, and the housing approval backlog provides plenty of motivation to act.