This forest fire began near Watson Lake, Yukon, on Thursday. It was one of 21 wildfires sparked in the area that evening alone. (Yukon Wildland Fire Management)

Health officials in the Yukon urged people to limit their outdoor activities as much of the central and southern portions of the territory remained under a blanket of forest fire smoke on Monday.

The smoky air conditions came from 64 wildfires burning across the Yukon, especially in the Watson Lake, Teslin, Dawson and Carmacks areas, as well as from fires in neighbouring Alaska.

"What to do about it is actually fairly simple: to stay indoors on the heavy smoke days, and to limit exertion," Dr. Brendan Hanley, the Yukon's medical officer of health, told reporters in Whitehorse on Monday.

An open-fire ban that was imposed across the territory last week remains in place this week. As well, fire officials recommend refraining from backcountry travel, and paddlers should not travel on the Teslin River.

Extra firefighters from Alberta, N.W.T.

Extra fire crews and equipment have been brought into the Yukon from Alberta and the Northwest Territories, at least until the situation stabilizes.

But their stay may be an extended one. Environment Canada is calling for more hot and dry weather, with daytime temperatures forecast to remain between 24 C and 26 C all week.

The fire danger is rated as high everywhere in the Yukon except Carmacks, where it is extreme.

The serious fire risk in the territory even prompted assurances by Premier Dennis Fentie that there is no need to panic.

"I first want to make the point, and be abundantly clear, that the Yukon is not in an emergency situation," Fentie said, adding that no communities are being threatened at this time.

About 40 new wildfires have been reported since last Thursday across the Yukon, with most of them burning in the Watson Lake area to the south.

Firefighters are also battling five wildfires in the Teslin district, four of which are burning on the south side of Teslin Lake.

While there is currently no need to evacuate any communities, fire officials said the flames pose a threat to several mining camps and remote wilderness cabins.

Those properties have been outfitted with sprinkler systems, and fire officials are closely monitoring them.

In total, there have been 104 wildfires in the Yukon so far this season, burning about 153,580 hectares of forest.