"Residents nearby are advised to close windows and doors and keep medication on hand if suffering from a respiratory illness."
There are no reports of people being injured.
Meanwhile, residents in Western Australia's south are being warned to prepare to defend their homes after a flare-up of the Merivale bushfire.
People living in the areas of Stockyard Creek and Mullet Lakes are warned the fire poses a possible threat to lives and homes.
The fire is contained but not under control and is slowly burning in a south-westerly direction.
"The fire is burning in bushland between Kirwan Road, Fisheries Road, Jim Ovens Road, Dunn Rock Road and the Esperance coastline," WA's Department of Fire and Emergency Services said in a statement.
"The fire has flared up on the western side of the fire."
Official advice for the fire was downgraded to watch and act alert overnight but has since been revised up.
More than 200 firefighters and 100 pastoralists have been fighting this and two other fires across the Shire of Esperance.
Advice alerts also in place for Salmon Gums and Grass Patch to the north of the coastal town and the Thomas River-Poison Creek area of Cape Arid National Park to the east.
There is also a severe fire warning for parts of the Pilbara, the Goldfields Midlands and Midwest Gascoyne with the Bureau of Meteorology forecasting hot, dry and windy conditions.
The Salmon Gums and Grass Patch fire left four people dead, including local farmer Kym Curnow, who was hailed as a hero for saving several people from driving into the inferno before becoming trapped himself.
Norwegian national Anna Sashohova Winther, 29, British man Thomas Leslie Butcher, 31, and German woman Julia Kohrs-Lichte, 19, also died trying to outrun the fire.
Also in the state's south, the Department of Parks and Wildlife is conducting a hazard reduction burn about 20km northeast of Manjimup.
- AAP
