Assistant chief officer Jon Henderson said: “Crews have worked tirelessly in challenging conditions, including steep and often inaccessible terrain, supported by a robust tactical plan.
“Their efforts have involved working with landowners and partner agencies to establish and maintain fire breaks to contain the spread of fire, limiting further damage and protecting surrounding infrastructure.
“Although we have made substantial progress, this remains a live operational incident and firefighters will remain in attendance until the area is safe.
“We continue to ask the public to avoid the area, respect all road closures and cordons, and follow the advice of emergency services at all times.”