A Country Fire Authority investigator has found that an electrical fault caused a fire which destroyed a house at Bessiebelle last Friday.

A police spokesman said the CFA investigator and Warrnambool crime investigation unit detectives examined the scene and concluded the cause of the blaze was not suspicious.

"It has been determined the cause of the fire was an electrical fault," the police spokesman said.

Friday: Flames as high as five metres greeted firefighters when they arrived to find a house at Bessiebelle fully ablaze on Friday morning.

Firefighters were called to the property on the Heywood-Woolsthorpe Road about 1.30am and initially thought the occupant may still be inside.

CFA commander Brett Gladki said the flames were five metres high above the roof by the time he arrived on scene about 2am.

For much of the first hour of fighting the fire, Mr Gladki said they were concerned that the occupant may have been inside at the time.

He said that created "a real sense of emergency" during the initial phase of tackling the fire. "We had to treat it as if there was someone in there," he said.

However after about 45 minutes they were able to track down the owner of the house who was away camping at the time of the blaze which had destroyed his home and belongings.

Mr Gladki said the fire must have been smoldering for a long time before it took off, sending flames shooting out the windows and doors.

A woman who was driving past noticed the back of the house on fire and raised the alarm.

"The fact it was an asbestos-clad house with a tin roof which had collapsed made it hard to extinguish," Mr Gladki said.

Unable to send firefighters inside to battle the blaze, crews were forced to do an external defensive attack on the house.

It took the five fire units more than an hour-and-a-half to bring the blaze under control.

Mr Gladki said because the property was so isolated, they had to have a number of tankers to bring water to the site.

A fire investigation will be carried out on the property today, something that was standard procedure when a house was so badly burnt, a CFA spokesperson said.

An advice message was issued on the Vic Emergency app about 4am warning residents of smoke in the area and that it would be visible throughout the day.

Nearby residents were warned to keep their doors and windows closed due to the lingering smoke.

Fire units from Warrnambool, Port Fairy, Bessiebelle, Orford, Heywood and Broadwater attended the blaze.

One appliance remained on scene overnight to monitor the smoldering ruins.