Emergency services were alerted to a unit fire in Shaws Road, Werribee this afternoon.
Fire trucks arrived on scene within eight minutes to find a single storey unit fully involved in fire and beginning to spread to an adjoining unit.
Firefighters donning breathing apparatus worked to prevent the fire from spreading to the adjoining unit.
The fire was brought under control at 1.33pm.
Both units were unoccupied at the time of the fire but experienced significant damage.
Authorities are currently on scene to determine the cause of the fire and crews will remain to ensure the fire is completely extinguished and the area is safe.