The woman and her child had been away from the property for an extended period of time and a friend had been keeping an eye on the property until they returned, police said.

Fire crews were called to the Gleeson Street home about 3.30am on Saturday to fight the blaze which took about 40 minutes to bring under control.

Detective Senior Constable Craig Wastell, of Warrnambool Criminal Investigation Unit, said it appeared the fire started in the loungeroom area of the home.

He said the amount of damaged caused by the blaze made it too dangerous for investigators to enter the property on Saturday.

“We couldn’t go in because the roof tiles were falling down while we were there, it was too unsafe,” he said.

Police were investigating whether someone may have been illegally squatting at the property on the morning of the fire. “We have a few lines of inquiry,” he added.

On Sunday morning, arson chemists from Melbourne’s Arson squad were on scene but were unable to determine the exact cause of the fire.

Warrnambool CFA station officer David Black said three CFA trucks attended the blaze in the fibro-cement sheet single-storey home. 

“It looks like the dwelling will be lost,” Mr Black said.

“It was an extensive fire.” 

Mr Black said overgrown grass and shrubs outside further fueled the fire and made the operation more complex.

“We had a grass fire at the same time as we had a house fire,” he said. 

He said the fire was a timely reminder to the public to regularly maintain their homes.