UPDATE, Monday, 10am:
Crane hire business owner Greg Waldron said the site would be fenced off.
He was busy on Monday morning moving trucks and equipment and said he was expecting an insurance assessor to examine the property when an assessor was available.
"There was a fire here last night," he said.
Mr Waldron said police had confirmed the cause of the fire was not suspicious, which allowed the trucks and machinery to be moved from the premises.
The damage appeared to be mostly contained to the southern half of the shed on the industrial estate block.
At Monday, 8.30am:
Firefighters battled a blaze in Merrivale on Sunday evening with flames shooting up to 20 metres into the night sky.
A Fire Rescue Victoria spokesperson said firefighters rushed to the 4B Crane Hire factory shed at 11 Robson Street.
"Firefighters from FRV and the Country Fire Authority responded to a fire in Warrnambool after a call to Triple Zero (000) just after 8pm," she said.
"FRV crews arrived to the Robson Street scene within seven minutes to find flames and smoke emitting from large shed.
"Firefighters worked to contained the scene with the incident declared under control at 9.25 pm.
"Victoria Police also attended the incident. The cause is currently undetermined but is not being treated as suspicious," she said.
It's understood that nearby residents, who were evacuated, have now been invited to return home.
At Monday, 8.05am:
A pot belly stove fire lit and left alight is believed to have sparked a factory fire in Warrnambool on Sunday night.
Warrnambool police Sergeant Paul McGovern said police crime scene officers were involved in securing the site and further investigations were expected to be carried out on Monday.
"The suggestion is that a pot belly stove was lit in the afternoon and left burning," he said.
"It had not been started since winter last year and that's what is suspected to be the cause of the fire at this stage."
A police arson chemist and a Fire Rescue Victoria investigator are expected to examine the fire scene today.
Sunday night: A fire has engulfed a warehouse in the industrial area of Merrivale in west Warrnambool.
The industrial warehouse in Robson Street was "completely involved", according to a CFA spokesman.
As of 8.30pm on Sunday the fire was still not under control and there remained a "risk of further exposures" to neighbouring buildings.
Six fire trucks were on the scene in an effort to control the fire.
It was not known what the warehouse contained, nor was the source of the fire clear.
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