The International Council on Monuments & Sites UK (Icomos) has raised concerns over proposals from Shropshire Homes to redevelop the former Aga Foundry in Coalbrookdale.
It was revealed last week that Icomos had objected to the proposal, and now the details of its concerns have been made public, with the group suggesting that world heritage watchdog Unesco should be consulted on the plans before any decision is taken.
In a letter to Telford & Wrekin Council, which will decide on the proposals, Icomos says that is it worried the development could have a "potentially highly negative impact on outstanding universal value" on Ironbridge's valued world heritage status.
Earlier this year another major UK world heritage site, Liverpool's waterfront, was stripped of its status after Unesco said it's heritage value had been diminished by new buildings.
Shropshire Homes wants to build 101 homes on the Coalbrookdale site, which closed in 2017.
In its letter Icomos, which advises Unesco, says it should have been alerted earlier to the proposals.
The organisation questions why Telford & Wrekin Council had not contacted it about the plans, despite recommendations to do so.
It also outlines its concerns about the impact of the development.
The letter, from Peter Marsden, chairman of the Icomos-UK World Heritage Committee, says: "As an industrial landscape the site was also ‘the focus of international attention from artists, engineers, and writers’ who came to view the new technologies.
"In sustaining outstanding universal value, it is thus essential that the idea of an industrial landscape is perpetuated, that all aspects connected with Abraham Derby and his production processes are conserved, and that the way this industrial landscape attracted artists and writers as well as engineers can still be appreciated."
He raises concerns that the "lower reaches of Coalbrookdale will be transformed from an industrial landscape into a dense, high-rise housing estate", and that 'the remnants of structures related to Abraham Darby, now overlain by waste materials, will not be preserved'.
He adds: "The views of the Dale from a network of paths and viewpoints will be highly compromised and thus their ability to promote understanding of industrial processes and their attraction for 18th century writers and artists."
A spokesperson for Telford and Wrekin Council said: “The planning applications for the former Aga casting works in Coalbrookdale are live and yet to be determined.
“The local planning authority (LPA) Telford and Wrekin Council does not comment on live applications. Should there be a resolution, it will be made available through the planning committee in due course.
“The LPA is following process and all necessary requirements to consult statutory consultees.”