The Northern Ireland Fire and Rescue Service (NIFRS) were on the scene of a blaze in the Spelga Dam area of the Mournes on Monday as they worked to manage the latest wildfire of the past few days.
There had been fires in other locations of the Mournes, as well as the nearby Hen Mountain and Cock Mountain as unseasonably dry weather left the conditions ripe for fires to spread.
There were also fires in the Cave Hill and Black Mountain areas of Belfast last week.
On Sunday night, the fire service were called to a large gorse fire at Spelga Dam at around 7.35pm covering appromximately 20 acres, with a mile-long front.
A watching brief was kept overnight into Monday morning with one pump and one Land Rover, when 24 firefighters were deployed and four pumps used.
The Spelga Dam fire is believed to have been started deliberately.
Mr Swann, whose Stormont department oversees the work of the fire service, expressed his support for the work of the firefighters involved in the operations in a statement.
“I want to commend the Northern Ireland Fire and Rescue Service for its response to the shocking wildfires that we have seen over the last week,” he said.
“These fires are causing untold damage to our environment and are also very challenging for NIFRS.”
He continued: “I pay tribute to each and every one of our firefighters who have worked tirelessly in extreme circumstances to bring these fires under control.”
On Friday, the fire service warned that conditions were “ripe” for wildfires to spread.
The unseasonably dry and warm conditions are set to change in the coming days.
Steven Keates, a Met Office meteorologist, said: “Looking at the month of March, you would normally expect about 87-90% of the month’s rainfall at this stage.
“In Northern Ireland it’s in the range of 40-50% depending on where you are.
“It’s been quite a bit drier than average. It’s also been quite a sunny month, with about 150% of the average sunshine up to and including yesterday. And it’s also been warmer than average.
“All that has combined to make things quite dry, and after a milder winter there’s probably more vegetation around than normal, so plenty of fuel on the ground.
“And it’s also quite breezy, so that’s all combined for wildfire risks.”
There was a high temperature of 17.4 degrees Celsius in Castlederg, Co Tyrone on Monday afternoon as the recent sunny weather continued. But things are due to turn “much colder” in the week ahead, Mr Keates said.
“There will be some showers, with bits and pieces of rain from time to time, and I believe the air will be cold enough for some snow – I think for Northern Ireland I wouldn’t get too excited about it but there may be some snow on the hills and colder areas.
“The ground is quite warm so the snow will struggle to stay, so I don’t expect there to be much disruption but it will certainly feel much colder.”
The meteorologist said the weather would likely begin to change from Wednesday morning onwards.