More than three-quarters of farmers reject the Scottish government's Galloway National Park proposal, with many failing to see any benefits it would bring.
Key concerns raised include potential disruptions to the planning system and a lack of transparency in the consultation process.
The region was chosen from a five-strong shortlist after a lengthy review of criteria, despite concern from rural and farming groups.
If given the official designation, Galloway will be the first national park in the UK in about 15 years.
NFU Scotland's latest survey shows that 76% percent of farmers strongly oppose the move, as many say it would fail to deliver any tangible advantages.
Other concerns highlighted include public access problems and uncertainty surrounding funding for the project.
Over the past three years, NFU Scotland has conducted multiple surveys to gauge opinions regarding the potential establishment of a national park in Galloway.
The union's regional chair for Dumfries and Galloway, Stewart Wyllie said there were no details on how the national park would be funded.
He said: "At a time when public resources are stretched across essential services like healthcare, education, and social care, it is clear that a national park is not a priority for the public, nor for this region’s farmers.”
Scottish farmers have also raised concerns about the potential impact on the agricultural sector, including the risk of stifling growth, innovation, and development.
And alarm has been raised over the likelihood of land property prices being driven up, further limiting local housing stock and exacerbating affordability issues for rural communities.
Throughout the consultation process, many farmers have expressed frustration over what they perceive as a lack of transparency and engagement from consultation lead body NatureScot.
Some farmers described the proposal as a 'fait accompli', suggesting that the process had been pre-determined without meaningful consideration of opposition voices.
Mr Wyllie said thar many farmers had described it as a ‘cloak-and-dagger’ approach, where key details about the park’s operation remain unknown.
"In places like Loch Lomond and The Trossachs, as well as the Lake District, farming businesses have struggled due to the prioritisation of tourism over agricultural livelihoods.
"We fear similar consequences if a new national park is established in Galloway," he concluded.
