Scottish Natural Heritage has written to Aberdeenshire Council revealing it plans to uphold an objection to a golf development proposed by Donald Trump.
There have been concerns about geese in the area
The US tycoon hopes to create a £1bn golf range at Menie, however the heritage body SNH claim it will seriously damage a nature site.
Its initial objection - made in May - was met by amendments to the proposals.
However in a letter to the council SNH concluded that these would not protect the site from destruction.
It has reiterated concerns that the development would offer potential threats to wildlife as part of the land is a Site of Special Scientific Interest (SSSI).
David Bale, SNH's new area manager for Grampian, said: "This site at Menie with its huge wild sand dunes is part of the largest dune system in Scotland, stretching from Newburgh to Bridge of Don.
"The Menie sand dunes are not like the majority of other UK sand dune areas - if they are not able to continue to shift and change, what makes them special will be lost.
"As the development of a golf course at this location would cause such significant damage to the Site of Special Scientific Interest, we have maintained our objection to this part of the proposal.
"We are still clear that building the championship golf course on the SSSI will inevitably damage it."
It would now be up to Aberdeenshire Council to assess the organisation's advice alongside other factors, including the Grampian economy and public services, he added.
The US tycoon's plans at Menie include two golf courses and a five-star hotel, and could create 6,000 jobs.
Developers said it could generate tens of millions of pounds for the local economy and secure hundreds of jobs.
Scottish Enterprise Grampian said it was excited about the potential for economic growth the development would bring.
Estimates for the cost of the project have ranged from £300m to £1bn.