How Central Coast Council's Planning Portal Ended Up With Hundreds of Duplicate Property Images — and Why It Took Years to Fix

Central Coast Council is working through a backlog of duplicate and mismatched images embedded in its online Development Application (DA) portal, a problem that traces directly to a chaotic data consolidation carried out between 2020 and 2022 while the council was under state-appointed administration. The cleanup, which council staff began flagging internally earlier this year, affects hundreds of property listings across the Gosford and Wyong local government areas.

The timing matters. The council only emerged from administration in May 2022, after a financial crisis that saw it accumulate more than $565 million in debt — a figure confirmed in the public administrator's final report. That recovery period forced rapid digitisation of planning records that had been held separately across the former Gosford City Council and Wyong Shire Council systems, which merged in 2016 but never fully unified their back-end databases. The image duplication is a direct symptom of that rushed merger work.

What Went Wrong in the Data Merge

The two legacy councils ran different document management systems for their respective DA archives. When administrators directed staff to migrate everything into a single cloud-hosted portal — a project partly overseen by the NSW Department of Planning and Environment under its Planning Portal rollout — images were batch-imported using automated scripts. Those scripts, according to council planning documents tabled at the February 2026 ordinary meeting, failed to detect when identical image files were already present under different reference numbers. A single aerial photograph of, say, a Terrigal Drive property or a block on Mann Street in Gosford CBD could appear attached to three or four separate DAs.

The practical consequence for residents and developers is real. Architects and certifiers searching the portal for site history photographs have reported pulling image sets that mix photos from adjacent or unrelated lots. The Central Coast chapter of the Australian Institute of Architects raised the issue with council's planning directorate in late 2025. For a region where housing development pressure is acute — median house prices in suburbs like Woy Woy and Kariong have risen sharply as Sydney commuters seek more affordable options along the Intercity rail line — any friction in the DA system carries economic weight.

The Path to a Fix

Council's Information Technology and Planning teams have been running a deduplication project since March 2026, using a combination of hash-matching software and manual review for the most complex cases. Staff have prioritised active DAs first, then archived applications going back to January 2018, which is when the unified portal launched for public submissions.

The work is not trivial. Council's DA register lists more than 14,000 applications lodged since the 2016 amalgamation, and staff have estimated that roughly 8 percent of image attachments across that dataset carry some form of duplication flag — a conservative internal estimate, not an independently audited figure. Properties along the Gosford CBD renewal corridor, including blocks adjacent to the Gosford Administration Building on Donnison Street, are among those with the most complex records because they attracted multiple overlapping DAs during the renewal planning phase from 2017 onwards.

State government oversight adds another layer. The NSW Planning Portal is ultimately administered by the Department of Planning, Housing and Infrastructure, and any structural changes to how attachments are stored require sign-off from Sydney. That approval process slowed the project's start by several months, council documents show.

For residents and developers currently navigating the system, council's planning counter at 2 Hely Street, Wyong, and the Gosford service centre on Mann Street can provide verified image sets for specific properties on request. Council has also advised that any DA lodged after 1 March 2026 is unaffected, as the new upload validation rules were applied from that date. The broader archive cleanup is expected to be completed by the end of the third quarter of 2026 — a deadline council staff have described in planning reports as achievable but contingent on current staffing levels holding through the winter leave period.