They had fled across the border to Bangladesh amid heavy fighting between the Myanmar military and rebel insurgents in Rakhine
At least five workers were injured while trying to douse the flames.
Deko Accessories, a button factory at Hemayetpur, caught fire around 8am, said Inspector Shahazur Sheikh of Savar Fire Service.
Five firefighting units rushed to the spot and extinguished the fire after an hour, he told bdnews24.com.
The cause of the fire was not yet known, said the Fire Service official.
In the other incident, a workshop of an Envoy Group factory in Ashulia’s Jamgora area caught fire around 8:30am.
The flame was doused within 30 minutes, said Senior Station Officer Abdul Hamid Mia of Dhaka EPZ Fire Service.
There were no casualties and the cause of the fire could not be indentified yet, he said.