A Watch and Act warning has been issued for residents in Minhamite, north of Hawkesdale.
The large grass fire has already destroyed 120 hectares and is travelling in a westerly direction.
Firefighting tankers and aircraft are working to control the fire.
The grass fire, which was first reported at 1.30pm, is on a property along the Penshurst-Warrnambool Road at Minhamite.
A Country Fire Authority media spokesman said the cause of the fire was not known at this stage.
Smoke is visible from as far as Warrnambool and Mortlake.
The CFA has advised residents in the area to:
-Check and follow your bushfire survival plan & prepare for a bushfire in your area.
-If you plan to leave or do not have a survival plan, leave now.
-Turn on your vehicle headlights and drive slowly; smoke will make it difficult to see.
-If you have a survival plan, well prepared and actively defended homes can provide safety.
-If you are away from home; do not return.
-If time permits, check your neighbours to see if they are monitoring conditions.
-If you are experiencing any symptoms that may be due to smoke exposure, the Department of Health advises people to seek medical advice or call Nurse on Call on 1300 606 024.
For general bushfire information:
Victorian Bushfire Information Line (VBIL) on freecall 1800 240 667 or www.cfa.vic.gov.au.
ABC Local Radio, commercial and designated community radio stations or watching Sky News TV.
Deaf, hard of hearing, or have a speech/communication impairment can contact VBIL via the National Relay Service on 1800 555 677.
Road closures: Check www.vicroads.vic.gov.au