Detective Senior Constable Richard Hughes, of the Warrnambool police crime investigation unit, said a shed at a property in Warrnambool's Wooles Avenue was set alight about 4am on Wednesday.

He said a passerby contacted emergency services after noticing the shed was on fire and within close proximity to a neighbouring property.

Detective Senior Constable Hughes said the shed and its contents, including an old television and pedestal fan, were damaged.

"Inside the shed looks like a gallon drum," he said.

"It seems someone has gone in and set fire to whatever they could, it is a bit weird."

Detective Senior Constable Hughes said a nearby fence was also burnt.

He said the premises was an unoccupied public housing property.

"It's very lucky the neighbouring house didn't catch fire," the detective said.

Warrnambool fire station officer Troy Cleverley said it appeared the small shed was burning for some time before a passerby noticed it and contacted emergency services.

He said it would have taken less than five minutes to bring under control.

Anyone with information is urged to contact Warrnambool police or Crime Stoppers.

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