Police suspect an arsonist was behind a blaze that gutted Paint West on Picton Road, causing at least $100,000 damage in the early hours of Saturday.

FESA was called to the fire about 3am and four fire fighters wore breathing apparatuses to battle the blaze.

It took more than an hour before the fire was extinguished.

Police, Western Power and crews from Bunbury Fire and Rescue and Bunbury Volunteer Fire and Rescue attended the scene.

FESA handed the investigation to the arson squad as it was deemed suspicious.

Neighbouring business owners gathered at the scene on Saturday, waiting to hear the damage bill.

Knot Just Frames owner Rose Bedggood said her business – next door to Paint West – had suffered collapsed ceilings and significant smoke damage.

“It leaves a sick taste in your mouth,” Mrs Bedggood said.

Bunbury police officer in charge senior sergeant Phil Nation said witnesses reported seeing a motorbike being ridden away from the complex and hearing a window smash close to the time the fire was reported.

Paint West was the sixth local business to go up in flames in the last 12 months, bringing the business damage bill to $6 million across the city.

Last month the Rivers Store on Symmonds Street suffered close to $150,000 damage when a fire started in the store’s air conditioning unit.

A deliberately lit fire caused $2 million to Dynamic Print on Strickland Street in August last year.

Three people were seen peering into the Siesta Bedding store on Spencer Street about 20 minutes before it was consumed by fire in March last year.

Aristos restaurant’s food processing plant in Davenport and the Highway Hotel on Spencer Street were burnt in accidental fires last year.

Sergeant Nation said the spate of fires at local businesses was not entirely unusual as businesses, like homes, were at risk of electrical faults.

He said police had not been able to determine the causes of the suspicious fires, which could be difficult because “fires, by their nature, destroy a lot of evidence.”

Sergeant Nation said arsonists needed to consider the harm their actions could cause.

“At this time of year any small fire has the potential to put lives at risk,” he said.

Sergeant Nation urged anyone with information about the fires to call Bunbury police on 9722 2111.