The National Trust of Australia (NSW) has listed the controversial Manyana Beach Estate as an area of significant natural heritage value.
Manyana Matters Environmental Association (MMEA) spokesperson Jorj Lowrey welcomes the move.
"The listing is a major breakthrough in the fight to stop the development from going ahead," she said.
"It reframes the perspective on this bushland and vindicates our campaign to save it."
Graham Quint, Director of Conservation for the trust explained their reasoning.
"Listing on the Trust Register is recognised as an authoritative statement of heritage significance of an area site, item or building, and, by listing such items on the Register, the Trust hopes to advise the public of the value of Australia's national heritage," he said.
The National Trust, which has named the site the Manyana Landscape Conservation Area, pointed to its biodiversity and significance to the local community in the aftermath of the Currowan Mega-Fire as key reasons for the listing.
"It has scientific and nature conservation significance as a rare surviving wildlife corridor and habitat for endangered species," the National Trust wrote on its listing.
"The area has high aesthetic significance for the local community particularly as so much of the adjoining bushland has been severely burnt."
The listing comes after surveys conducted by local researchers found evidence of several threatened species in and around the site.
This includes the Dusky Antechinus, Glossy Black Cockatoo and Gang-Gang Cockatoo, all of which have recently been added to the Federal Government's priority list for urgent management intervention in the wake of last summer's bushfires.
Ecologist and local resident Brendan Ryan says these recent sightings highlight the inadequacy of the ecological report submitted by developer Ozy Homes to the Federal Environment Minister last week as part of their referral.
"It's woefully inadequate. It only assesses seven out of a potential 51 species that are listed on the Environmental Protection and Biodiversity Conservation (EPBC) Act, and there is no mention of threatened ecological communities," he said.
"It is not a serious attempt to evaluate the ecological impact of this project after the catastrophic fires that decimated the Conjola National Park and surrounds."
The proposed development and its effect on federally listed species are currently being reviewed by the Federal Environment Minister.
"There's so much at stake for conservation dependent plant and animal species," Mr Ryan said.
"I urge the Minister to call this project in as a controlled action in order for the cumulative impacts to be properly assessed after the devastating fires."
Public submissions on the project's impact can be emailed to email@example.com by July 7 with ref 2020/8704. Access the Ozy Homes referral documentation here .