Plans to extend the ban on burning heather on deep peat have been called "deeply concerning" for upland farmers, particularly those managing moorland areas.
The NFU said the government's proposals, which have been sent out for consultation, came at a time when farmers already faced "huge challenges".
The government said the move would mean an extra 146,000 hectares would be covered by regulations banning heather burning.
The area falling within the regulations would involve changes to Less Favoured Areas, replacing the existing focus on Sites of Special Scientific Interest that are also Special Areas of Conservation and/or Special Protection Areas.
The definition of deep peat would also be revised, so that it is counted as anything over 30cms rather than 40cms, bringing more areas within the regulations.
Any prescribed burning would need to be done under a strict licence, which the government said would be issued where there is a ‘clear need’, citing reducing wildfire risk as an example.
The licensing system would require applicants to ‘successfully explain’ why alternative methods have not, or would not, work.
Applicants would also have to show how they intend to move the land away from the need to burn in future in order to receive a licence.
It’s also been proposed that one or more people carrying out a burn under the regulations must have completed a mandatory training course.
Responding to the news, NFU deputy president David Exwood said it would be "deeply concerning" for the upland farming sector.
He said they already faced "huge challenges" with the recent closure of the Sustainable Farming Incentive (SFI) scheme, reductions in direct payments and changes to inheritance tax from April 2026.
“Changing peatland management practices could threaten the viability of livestock farming in these unique landscapes," Mr Exwood added.
“We will also continue to engage with Defra to ensure it understands the importance of upland farming systems, for food production and also for the vital peatland restoration work farmers are already doing.”
Nature Minister Mary Creagh said: "Our peatlands are this country’s Amazon Rainforest – home to our most precious wildlife, storing carbon and reducing flooding risk.
"The UK has 13% of the world’s blanket bog. A rare global habitat, it is a precious part of our heritage, and that is why we‘re announcing a consultation on these measures to ensure deep peat is better protected."
The online consultation will be open for eight weeks, closing for responses on 25 May.
