DHAKA (AFP) - Bangladesh on Wednesday ordered an inspection of all its 4,500 garment factories and arrested bosses of a plant at the centre of the latest deadly blaze as it tackled the industry's "alarming" safety record.

As part of the safety overhaul, authorities ordered the garment industry to end the practice of locking exit doors during production in the aftermath of two factory infernos since November in which a total of 118 workers were killed.

"The number of workers dying and being injured in fire incidents has risen alarmingly, creating an adverse impact at home and abroad," Habibul Islam, the national chief factory inspector, told AFP.

The fires in the factories where clothing for retailers including Walmart and Sears were being made have highlighted the industry's notorious safety conditions, raising concerns about the future of the US$20 billion (S$25 billion) sector.

Mr Islam said 20 inspection teams had begun to check whether the factories - most of which are on the outskirts of Dhaka - had fire and building safety permits and enough fire equipment and whether their exit doors were locked.

The locking of exits is banned under labour laws, but most of the garment manufacturers defy them in a bid to stop clothing from being stolen.

Mr Islam said managers had been told instead to employ more security staff and the inspectors had been instructed immediately to shut down any factories whose exit doors were locked.

The push for better safety was prompted by a fire on November 24 when 111 were killed at the nine-storey Tazreen plant in the Ashulia industrial district.

Having found the fire exits on lower floors locked and bolted, the workers fled to the top floor as the flames climbed. Many leapt to their deaths.

The tragedy prompted widespread protests in Dhaka and pledges by the government finally to get tough with the industry, one of the mainstays of the economy.

According to the factory inspectorate's figures, 139 workers died in factory accidents last year, up from 56 in 2011.

Around 700 garment workers have been killed since 2006, most of whom burned to death or died of smoke inhalation in factories where the gates were locked.

In the latest deadly blaze on Saturday, seven women were killed at the Smart factory in Dhaka when they found the fire exits locked.

Police arrested two of the plant's owners late on Tuesday after the father of one of the dead workers filed a case accusing them of gross negligence.

Spanish retail giant Inditex, owner of the popular Zara brand, has announced it has cancelled contracts with two of its suppliers, including a Bangladeshi manufacturer which allegedly sub-contracted the work to Smart.

Garment workers in Bangladesh, the world's second largest apparel maker, are often paid as little as $37 a month. The industry accounts for 80 percent of Bangladesh's annual exports.