Clouds of thick black smoke are billowing from a large fire at a factory in Sydney’s south-west, with one witness describing the noise during the fire as “bomb-like explosions”.

More than 20 fire crews with 100 firefighters were called to Yulong Close in Moorebank after the fire engulfed the Baker & Co food factory just before 2:00pm.

Aerial footage shows flames leaping from the factory as crews set up hose lines to try to bring the blaze under control.

The eastern wall of the factory came crashing down just before 5.30pm.

Firefighters initially hoped the fire would burn itself out, but they are now battling to prevent the spread of the blaze.

Emergency services have evacuated 200 people from 15 nearby warehouses.

About 100 residents from 40 nearby homes have also been evacuated and it is unclear whether they will be able to return on Tuesday night.

An evacuation centre has been set up at Chipping Norton Boatshed.

Fire and Rescue NSW has advised neighbouring residents to stay indoors and keep windows and doors closed.

Wattle Grove firefighter Inspector Kernin Lambert said several thousand litres of flammable liquid had escaped from the factory and ignited, causing intense fires behind the back of neighbouring houses.

“We’re now trying to launch a major attack on the actual factory itself,” he said.

“The houses are still in danger but we do have numerous firefighters in between the houses and the factory and we’re just trying to stop the fire from getting to those houses.”

Mr Lambert said the windy conditions were contributing oxygen and fuelling the fire, which was producing heat of more than 1000 degrees Celsius.

He said the wind was blowing the smoke away from nearby houses but they were monitoring for any changes.

There were concerns smoke might blow towards the Liverpool area.

The factory was evacuated and there have been no reports of any injuries.

Juliana Pino works at a nearby cafe and said it was an intense scene.

“There were bomb-like explosions going off in the actual factory so I think they’ve got chemicals and things with whatever they use down there,” she said.

“These poor people have lost their cars and personal items in the building.”

The area is adjacent to the M5 and traffic has been impacted.

Police and paramedics are also on the scene.