The state has been called on to "immediately cease all plans associated with the purchase of hill lands".
The Irish Natura and Hill Farmers' Association (INHFA) claimed that these purchases are "currently being driven" by the National Parks and Wildlife Service (NPWS), and are "undermining access to land" for young farmers.
Pheilim Molloy, the national president of the INHFA, said that current policy is "taking large areas out of agricultural use while also undermining the ability of young farmers to access land".
"At a time when there is growing concern around the number of young farmers entering the industry, it is galling to see these farmers blocked from entering the industry by a state body with massive resources," he added.
Molloy said there is concern among farmers that there will be an increase in these purchases due to a higher budget allocation for national parks.
Budget 2026 saw an allocation of €256 million for nature restoration and heritage for next year.
This includes a 20% increase in funding for the NPWS, including a 27% uplift in capital investment in Ireland’s national parks and nature reserves and its natura sites.
According to the Department of Housing, Local Government and Heritage, the funding will support the presentation of national parks and nature reserves.
Molloy said that, while the accumulation of land by the NPWS is seen by some as a positive in protecting nature, the absence of farming activity from our national parks "has undermined habitat conservation leading to biodiversity loss".
"For centuries local families were the boots on the ground protecting these unique habitats through conservation grazing, essential for the habitats and their wildlife.
"Currently many of our national parks are not in a great place, with invasive species such as rhododendron spreading, increasing habitat loss, and a deer population that is out of control and spreading throughout the country," Molloy added.
The INHFA president said: "It is time the NPWS spend the additional resources in getting [its] own house in order, address the many concerns inside the existing national parks...and target resources to dealing with the growing deer population [that] are also carriers of TB and tick-borne diseases."
He called on the state and the NPWS to abandon its plans to purchase additional lands "thus ensuring those young farmers that want to come into the industry have a route to do so".