Newcastle's inner-city residents group says Iris Capital and City of Newcastle are allowing "unchecked vandalism" of a heritage conservation area earmarked for the final stages of the EastEnd development.
Newcastle Inner City Residents Alliance has written to councillors urging them to "stand up for the public's interest when it concerns protecting Newcastle's unique legacy of heritage buildings".
Lord mayor Nuatali Nelmes said at the time that "action is progressing on the demolition of the non-heritage buildings so the site can be adequately contained" after police and Iris raised concerns about public safety at the site.
The buildings are in the council's City Centre Heritage Conservation Area but are not on the state heritage register.
The Newcastle Herald visited the redevelopment site on Sunday and found at least four open doors leading into derelict and vandalised buildings.
Five children were playing in two of the buildings, walking through broken glass, old mattresses, graffiti and piles of rubbish.
"Many inner-city residents and businesses are astonished at the apparent lack of concern ... by property developer Iris Capital and the City of Newcastle to intervene to help stop the damage and degradation of our city's historic legacy," the NICRA letter says.
"The buildings are targeted by vandals and roaming gangs who have also intimidated and harassed local businesses.
"Those bad players have damaged and defaced significant heritage buildings, including the impressive 1908 Municipal Building (not planned for demolition), adjacent to the 1970s Hunter Village shopping centre.
"Other targets include Blackall House in Newcomen Street (seems secure at present) and arguably Newcastle's oldest timber building still standing, at 74 King Street opposite the Newcastle Club."
An Iris spokesperson condemned the vandalism and said the company would start demolition before the end of the year.
"It's disgusting the vandalism which is occurring, and why parents are not better educating their children not to trespass and disrespect other people's properties," the spokesperson said.
"Demolition is a work in progress. Given the size of the site it's a major demolition scope and these take time.
"We are currently addressing the relevant council conditions of consent and service authority disconnection approvals. It's not a fast process."
NICRA spokesperson Brian Ladd said in the letter to councillors that someone had tried to burn down the timber building in King Street.
He said Iris had tried to secure the redevelopment site with locks, chains and timber hoardings but "appear to have abandoned" these attempts.
"On any given day of the week it is easy to find one of the doors ajar, and in recent days vandals have broken through protective hoarding at 74 King Street, leaving the door facing King Street open."
The Newcastle Club, which has spoken out publicly against the development due to its heritage and view impacts, recently engaged heritage architect Paul Davies to assess the 1860s building at 74 King Street.
Mr Davies concluded the developer's heritage consultant, City Plan, had erred in assessing the building and broader redevelopment site as having little heritage significance.
"The building has at least contributory significance (as set out in the LEP heritage listing) and is very likely to have high or even exceptional significance," he found.
Mr Ladd said it would be a "heritage loss" for the city if fire seriously damaged the Municipal Building.
"NICRA fears that the CoN might approve a badly damaged Municipal Building for demolition. This must not occur," he wrote in his letter to councillors.
Iris has lodged a development application for the final stages of the EastEnd development in an area bounded by Hunter, King, Newcomen and Thorn streets.
The National Trust raised questions in July about how the council had approved several buildings in the redevelopment zone for demolition.
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