COUNTRY Fire Authority officials and police have labelled the cause of the 450-hectare Stoneyford fire as suspicious.
CFA investigators and Warrnambool police crime investigation unit detectives will further examine the fire scene this morning to try and determine a cause.
Detective Acting Sergeant Wayne Ryan said this morning the fire could have started from up to four ignition points.
He said the fire was believed to have started from one point just off Scoullers Road, near the intersection with the Cobden-Stoneyford Road at Stoneyford.
"It is believed the fire could have originated from a number of separate points. We looked at one site late last night and the CFA investigator described it as highly likely as one of the seats of the fire," he said.
"While the cause of the fire is suspicious, at this stage we do not know how it started.
"Whether it was deliberate or some other unknown means we are unsure as yet.
"There is no evidence about how it started but it's definitely suspicious."
Detective Acting Sergeant Ryan said the fire started about 2.40pm and he called for any witnesses who saw anything unusual in that area, or a vehicle, to contact the Warrnambool police station CIU or Crime Stoppers.
Last night more than 30 CFA units and a number of aircraft battled difficult conditions to contain the 450-hectare Stoneyford fire.
The fire was stopped from spreading in the area but is not yet considered under control.
While the threat has been removed from the community and the Camperdown relief centre has been closed, the CFA asks residents to stay informed.