The ACT's largest controlled burn in 30 years has begun today at the Namadgi National Park in Canberra's west.
The burn at Smokers Trail is expected to cover 6,000 hectares and may take up to 10 days to complete.
Head of the Territory and Municipal Services (TAMS) Fire Management Unit Neil Cooper says the burn will be ignited from a helicopter because the area is so remote.
"You can't send crews down steep, rugged inclines and be miles from a vehicle," he said.
"But what we do with the helicopter is we fly along the ridge tops and we drop out these little [fire lighting] balls.
"There's a chemical reaction inside after about 30 seconds."
The burn will reduce ground fuel loads and the bushfire risk across the territory.
Mr Cooper says people should expect some smoke for the next few days.
"You know there may be a little bit of small inconvenience for six or seven days, but for that inconvenience we help look after the environment, look after the built assets and look after our water supply," he said.
Authorities are taking advantage of the cooler autumn weather for the large scale burn.
"We feel that Thursday the weather is improving a little bit, lots of lower humidity, we should get a fair bit of [fire] lighting in place," Mr Cooper said.
"Friday we should be able to build on that lighting into Saturday and Sunday."
The burn will be monitored day and night by ground crews.