The Rana Plaza in Savar collapsed at about 9:00 am (local time) with rescue work being carried out to pull out survivors from the rubble.
The eight-storey commercial building housed three garment units, a bank branch and around three hundred shops. Locals said around 6,000 workers used to work in the factories located in the building.
Most of the bodies were taken to the Enam Medical College from the site, which is located near the Savar bus stand. At least 108 people were killed in the incident, The Daily Star newspaper reported quoting officials.
Nearly 150 people were pulled out of the rubble alive so far. With few hundred more believed to be trapped inside, rescuers fear the death toll may rise significantly.
"Death toll touched 100. As the rescue campaign continued, we expect more bodies to be retrieved overnight," Fire Service Director General Brig Gen Ali Ahmed Khan said.
Home Minister Muhiuddin Khan Alamgir said, "The building might have collapsed due to faulty construction."
Zahidur Rahman, Director, Public Relations of the Enam Medical College and Hospital, said they had received 91 bodies.
The dead bodies and the injured were being retrieved from the debris with makeshift slides being made from cloth.
General officer commanding (GOC) of the army's Savar-based ninth division Major General Abul Hassan Sarwardy said army engineers and rescuers were forced to proceed "slowly and cautiously" to avoid further casualties.
"We are penetrating inside the structure slowly and cautiously, otherwise the building will collapse entirely causing more casualties," he told reporters.