At least 120 people were burnt to death as a fire swept through a garment factory on the outskirts of Bangladesh's capital, the chief of the fire brigade said on Sunday.

The fire at the nine-story factory in the Ashulia industrial belt started on the ground floor late on Saturday and quickly spread, trapping hundreds of workers.

"This morning we have recovered 120 dead bodies and the death toll could rise," Abu Nayeem Mohammad Shahidullah, director general of the fire brigade, told reporters.

Bangladesh has around 4,500 garment factories that make clothes for brands including Tesco, Wal-Mart, JC Penney, H&M, Marks & Spencer, Kohl's and Carrefour.