The Calder Freeway is closed in both directions between Woodend and Kyneton due to a grass fire near the freeway in Carlsruhe.
The fire is not yet under control according to VicEmergency and is travelling in a north-westerly direction from near Cobb and Co Road along the Calder Freeway.
Motorists heading towards Bendigo are being urged to take a detour at Black Forest Drive, through Woodend, Tylden and Kyneton before returning to the freeway via Burton Avenue.
Southbound traffic, heading towards Melbourne, can detour at Edgecombe Street and follow Trentham Road through Woodend.
The Department of Transport is asking motorists to avoid the area and to follow the direction of emergency services as conditions change.
“If driving through areas of smoke, we suggest motorists use their headlights on low-beam to make sure they can see and be seen by others,” the Department of Transport said in an online statement.
“Windows should be closed and air-conditioning set to recirculation to reduce the smell of smoke inside the car.
“If visibility deteriorates and it becomes unsafe to continue driving, motorists should pull over. The use of hazard lights and parking off the roadway will help avoid collisions, which are common during bushfires.”