The National Trust has hit out at those camping on its land and leaving behind "substantial" litter.
The conservation charity said its rangers are now spending 20 per cent of their time clearing up after visitors instead of helping to protect nature and wildlife.
In addition, there have also been instances of rangers being "verbally abused during polite requests to have campers move on".
The National Trust said that since the easing of lockdown restrictions, Northern Ireland’s popular beauty spots including the Mourne Mountains, Murlough Nature Reserve and parts of the Causeway Coast have seen significant increases in the number of people camping, and a spike in the number of camper vans parking at beauty spots overnight, without permission.
This has led to a dramatic increase in the amount of discarded equipment and litter being left behind at countryside and coastal locations.
Clare O'Reilly, Mourne Ranger, said the charity had seen "a notable increase in this behaviour at our sites in the Mournes - both at Bloody Bridge and Slieve Donard, and in various parts of Murlough Nature Reserve, including the main board walk.
"The rubbish left behind is usually substantial," she said.
"We routinely clear up to four full bin liners from each camp, and deal with the aftermath of damaged habitats from fires, broken glass and disposable BBQs.
"Some of this litter can be buried into the 6,000-year-old sand dunes, which then slowly release shards of glass and sharpened metal, creating a serious hazard risk for children, adults, dogs, and our wildlife".
Rob Rhodes, Head of Rangers at the National Trust said: "The sort of work we want to be doing at this time of year includes managing our flower rich meadows and caring for the wildlife that live there, and vital maintenance work to our network of paths and visitor routes.
"But this unsociable behaviour by some is taking up so much time that it’s affecting not only the upkeep of our sites, but taking our staff away from vital conservation work and engaging with visitors," he said.
"Leaving debris and litter behind can cause issues for wildlife such as injuring animals and destroying habitats. No one should have to clear up the mess that we are experiencing at some of our places".
