Sydney's duplicate image problem: how the city stacks up against London, Singapore and Toronto

Sydney's property and public-records databases are carrying a growing load of duplicate imagery, a problem that digital archivists and planning administrators say is quietly corroding the reliability of official records and costing agencies real money to fix. The issue sits at the intersection of two forces battering the city simultaneously: a housing construction boom that is generating tens of thousands of new development-application images every quarter, and ageing data infrastructure that was never designed to deduplicate at scale.

The timing matters. The NSW Government is under sustained political pressure to accelerate housing approvals across Western Sydney — particularly around the Bradfield City Centre near the new Western Sydney International Airport — and the Metro West corridor from Hunter Street in the CBD to Westmead. Duplicate images inside planning portals slow verification checks, inflate storage costs, and in some documented cases in other jurisdictions have contributed to approvals being matched against the wrong site photographs. Sydney has not yet publicly reported that specific failure mode, but digital records managers at several metropolitan councils have flagged the risk in internal working sessions this year.

What Sydney is doing — and where the gaps are

The NSW Department of Planning runs its ePlanning portal, which processes development applications across the state. The platform ingests thousands of site photographs, architectural renders, and environmental assessment images monthly. A February 2026 audit of local government digital records, conducted by the NSW State Archives and Records Authority, identified image duplication as one of three systemic data-quality issues affecting council systems, alongside metadata inconsistency and broken document links. The audit did not publish a specific duplication rate for Sydney councils, but the finding prompted at least four councils — including Cumberland Council in the city's west and the Inner West Council — to begin separate deduplication projects using perceptual hashing tools.

Cumberland's project, which began in March 2026 and is being run out of its Merrylands civic centre, is targeting roughly 400,000 images held across its property information system. Inner West Council, headquartered in Petersham, is taking a narrower approach — focusing first on images attached to heritage listings along the Parramatta Road corridor, where development pressure is highest. Neither council has published completion timelines or cost figures.

Real estate is a parallel front. Domain and REA Group, both of which operate major listing platforms drawing heavily on Sydney's hyper-active property market, have each publicly described investment in image-quality and deduplication tooling in their respective annual reports over the past two years. The Sydney market generates volume that strains any platform: CoreLogic data published in June 2026 recorded more than 28,000 residential properties listed for sale in Greater Sydney during May alone.

How Sydney compares internationally

London is the most instructive benchmark. The Greater London Authority mandated image deduplication standards for all 32 borough planning portals in 2024 as part of its Planning Data Quality Framework, giving boroughs 18 months to comply. Singapore's Urban Redevelopment Authority has operated a centralised image repository with automated duplicate detection since 2022, embedded inside its GoBusiness licensing platform. Toronto, which consolidated its planning data systems in 2023 following a city-wide digital infrastructure review, now runs hash-based deduplication across its Permit Portal in near real time.

Sydney has no equivalent mandate. The NSW Government has not yet legislated or formally directed councils to adopt a common deduplication standard, meaning the city's 33 metropolitan councils are free to act — or not — on their own schedule. That fragmentation puts Sydney closer to Melbourne's current position than to London's, though Melbourne's City of Melbourne council did adopt its own image integrity policy in late 2025.

For residents and businesses lodging development applications, the practical upshot is uneven. A builder submitting plans for a dual-occupancy in Blacktown may encounter a smoother digital process than one working in a council that hasn't yet addressed the problem. Advocates for planning reform argue the fix is straightforward: mandate participation in a shared NSW state image registry, similar to what Queensland began piloting through its MyDAS2 system last year. Whether the Minns government moves in that direction will likely depend on how loudly the problem surfaces in the next round of development backlog reporting, expected from the Department of Planning later this northern winter.