Eight fire engines have been pressed into service. "No one is injured...Efforts are on to extinguish the fire," Deputy Commissioner of Police (Central Zone) V B Kamalasan Reddy said.
The factory abuts a residential building.
The fire-fighters were facing some difficulty as the area is congested, a fire brigade officer said.
An eye-witnesses said that the fire started at around 2 AM, but the fire engines reached only at around 4.30 AM, and the fire was still not out.