Firefighters are battling a large gorse fire in the Slieve Donard area of the Mourne Mountains in County Down.
Twelve fire appliances and 58 firefighters have been at the scene since the early hours of Friday.
The NI Fire and Rescue Service (NIFRS) said that there is potential for further fires this weekend due to extremely dry conditions.
They urged people to avoid both the Bloody Bridge and Glen Road access points this weekend.
Slieve Donard is the highest mountain in Northern Ireland.
They said the area was unsuitable for wild camping, adding "we would ask the public to exercise due care and vigilance in relation to fire safety if out in the countryside during this current dry spell".
Sinn Féin MP Chris Hazzard thanked the NIFRS but said local agencies need "urgent help".
Huge thanks to @NIFRSOFFICIAL for ongoing efforts to tackle #Mournes wildfire today— Chris Hazzard (@ChrisHazzardSF) April 23, 2021
Please avoid Bloody Bridge / Donard Forest areas at all costs
Local agencies need urgent help from central govt to effectively deal with increasing wildfire problem pic.twitter.com/0TOAkk1nkR
In a statement, he urged people to "avoid the Bloody Bridge/Donard Forest area at all costs tonight and allow fire and rescue services the space to extinguish this fire safely".
"Whether accidental or deliberate, wildfires are incredibly dangerous. Today's fire will have caused widespread damage to an environmentally sensitive area, and will also unfortunately have proven deadly for local wildlife," he said.
BBC News NI reporter Kevin Sharkey at the scene
This fire has been running through the Mournes since early Friday morning.
Throughout the day, the constant movement of the blaze has challenged fire fighting efforts on the ground.
The fire shifted from the Bloody Bridge side to the Donard end.
With good weather expected to continue into the weekend, walkers and visitors are being asked to stay away from the Glen River and Bloody Bridge access points this weekend.
As night began to fall here, fire crews left the mountainside.
Rest, before the battle against this fire resumes in the morning.
SDLP MLA Colin McGrath said there was initial hope that the fire could be contained, but light winds caused it to spread down the eastern slope of Leganabruchan and eventually into Donard Forest in Newcastle.
Mr McGrath paid tribute to the firefighters' "bravery and determination", adding that the fire was visible from as far away as Downpatrick.
"Sadly, this will not only have a devastating impact on the natural landscape but the local economy of Newcastle that relies so heavily on the tourist product we associate with the Mournes," he said.
Mr McGrath said that most firefighters have now been withdrawn for safety reasons but they will be back at dawn when it is colder.
In a tweet, DUP Agriculture Minister Edwin Poots said the fire was "sickening".
Sickening that one human can cause so much damage to our environment and biodiversity in the beautiful Mournes.— Edwin Poots MLA (@edwinpootsmla) April 23, 2021
Thank you so much to the NIFRS and first responders. https://t.co/K3pnOiVJsl