The Department of Parks and Wildlife has issued a smoke alert for people driving on the Vasse Highway between Nannup and Busselton.
The smoke is from a prescribed burn being carried out today to manage bushfire risk.
The smoke is expected to affect the Vasse Highway and communities in the Nannup and Busselton area over the next couple of days.
If the smoke is particularly thick, it is recommended people shut doors and windows and turn off air-conditioners.
Smoke may reduce visibility on some roads and motorists should take care, turn on headlights and travel at appropriate speeds.
Motorist are also asked to watch out for fire crew working in the area.
People with asthma and pre-existing respiratory or cardiovascular illnesses should follow their pre-prepared treatment plan.
People with conditions exacerbated by smoke should take precautions in line with their medical advice for these circumstances.
More information on prescribed burns can be found at www.dpaw.wa.gov.au