More than 70 firefighters and 25 fire trucks were deployed to the blaze, which broke out in a whitegoods business on Canterbury Road around 2.30am.
Fire crews attempted to enter the building but were quickly forced to retreat due to the dangerous conditions.
Flames threatened to spread to an adjoining petrol station, where more than 100,000 litres of petrol were being stored, as well as two neighbouring homes and an equipment hire warehouse.
FRNSW mobilised three ladder trucks which were able to reach above each of the affected buildings and limit the potential spread of the fire.
Canterbury Road was closed as a result of the incident.
The occupants of one of the nearby homes were protected in place; however, no evacuations were required.
The fire took more than three hours of intense attack to bring under control.
FRNSW crews today remain at the scene, dousing materials which continue to smoulder in deep-seated areas of the fire.
The roof of the impacted building is believed to contain asbestos.
Currently, the roof is still wet from firefighting operations, which is helping to suppress any particles disturbed by the incident.
FRNSW is working with City of Canterbury Bankstown Council, the NSW Environment Protection Agency (EPA) and NSW Public Works to make the area safe.
Experts from FRNSW’s Fire Investigation and Research Unit (FIRU) will examine where and how the fire started.
Traffic on Canterbury Road continues to be impacted, with motorists advised to check http://livetraffic.com for updates.
