The Alliance for Bangladesh Worker Safety, which was set up after the Rana Plaza disaster and represents North American apparel brands including Wal-Mart, said remediation work had been completed in 24 factories and was underway in hundreds of others.
"It means only 24 factories (of those inspected) can now be called reasonably safe," Mesbah Rabin, managing director of the Alliance, told AFP.
The collapse of the Rana Plaza factory complex in 2013 killed more than 1,100 garment workers and sparked international outrage against the global brands who placed orders in the building's five plants.
The Alliance said it had asked the Bangladesh government to shut down 36 factories after they were found to be structurally unsafe and suspended ties with 77 plants that failed to address safety concerns.
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"There is still much to do to meet our five-year goals, but we've come a long way toward improving workplace safety in factories," said James Moriarty, executive director of the Alliance.
Fires in garment factories have dropped from 250 in 2012 to just 30 in 2015, with no fatalities that year, Moriarty said, citing Bangladesh fire department figures.
The South Asian nation is the world's second-largest garment exporter, according to the World Bank. It employs around four million workers and shipped clothing worth $26 billion last year, mainly to Europe and North America.
The Accord on Fire and Building Safety in Bangladesh, which represents around 200 European brands including H&M, Primark and Tesco has also taken an active role in investigating the country's factories.