Ontario's Ministry of Natural Resources says 12 of the 39 fires burning across the northeastern part of the province remain out of control.
The Parry Sound 33 blaze, which has raged for more than a week, remains the largest of the fires at just over 76 square kilometres.
Ministry spokesman Shayne McCool says ground crews, aided by waterbombers and helicopters, attacked the fire's perimeter on Saturday ``with generally good results.''
But McCool says the flames are now just seven kilometres away from a stretch of the Trans Canada highway, and southwest winds today could blow heavy smoke onto Highway 69 and into surrounding communities.
If the smoke is heavy enough, McCool says police may close a portion of the highway.
He adds that due to the extreme fire hazard, the zone where fire restrictions are in place has been expanded to areas south of the French River, from Georgian Bay east to the Quebec border, including Algonquin Park, and from Renfrew north to Mattawa.
Travel restrictions are also in place for parts of North Bay, Kirkland Lake, Sudbury, Pembroke and Parry Sound districts.
Hundreds of firefighters from across Canada, the U.S. and Mexico are helping the Ontario crews battle the forest fires.