Inspectors hired by Western retailers have been checking the structural safety of factories in the wake of the collapse of the Rana Plaza complex last year that killed 1,138 people.
But a dispute has erupted between Bangladesh's Inspector General of Factories and engineers from the group of retailers called the Accord over the concrete strength in the buildings.
The inspector general, Syed Ahmed, said his office has refused since April to review or close down six factories, employing hundreds of workers, deemed unsafe after inspections.
"It's a tricky issue," said Ahmed, whose office already closed 14 factories on the engineers' recommendations before the row broke out.
"Until the debate on concrete strength is resolved, we're not shutting down any factories recommended by the Accord," he told AFP.
The factory shutdowns have infuriated Bangladesh's influential garment manufacturers and resulted in more than 10,000 job losses, triggering labour protests and violence.
Bangladesh is the world's second-biggest clothing manufacturer and the $22 billion (16 billion euros) sector is the mainstay of the impoverished South Asian nation's economy.
But the sector -- with some 3,500 factories -- has a woeful safety track record, highlighted by the collapse of Rana Plaza last April on the outskirts of the capital in Bangladesh's deadliest industrial disaster.
The dispute centres on the estimated strength of the concrete in buildings made before 2005. Accord's inspectors put the concrete strength significantly lower than estimates from the country's main engineering university which advises the government.
The head of inspections for the Accord, representing 150 mostly European retailers, including H&M, Tesco and Benetton, said the factory inspector general's refusal to go ahead with the shutdowns was disappointing.
"We're disappointed that the inspector general did not close down the unsafe factories," Brad Loewen, the Accord's chief inspector, told AFP. "We're working with BUET (Bangladesh University of Engineering and Technology) on the concrete strength issue."
Officials from BUET, retailers and the International Labour Organisation were expected to meet later this week to try to resolve the dispute.
But one BUET professor said accepting the Accord's recommendations on concrete strength would prove disastrous for the garment industry.
"It may led to closure of some 40-50 percent of our garment factories," the professor said, speaking on condition of anonymity.
"But if they accept our estimate, it might lead to closure of only about 10 percent of factories. We think we are on the right side because we've more data on Bangladeshi factories," he added.