The country reported 119 deaths on Sunday, its highest-ever daily death toll from the pandemic, while new infections have been averaging nearly 5,000 for the past few days.
Officials blame the recent spike in cases on the highly contagious coronavirus Delta variant first identified in neighbouring India.
The majority of the South Asian nation’s 168 million population will be confined to their homes by Thursday as part of the restrictions, with only essential services and some export-facing factories allowed to operate.
The lockdown announcement sparked an exodus of migrant workers from the capital Dhaka to home villages on Sunday, with tens of thousands of people cramming into ferries to cross a big river.
The staggered implementation of the lockdown rules left thousands of workers in Dhaka forced to walk to their offices on Monday, sometimes for hours, in the sweltering summer heat.
Large columns of people were seen walking on the main roads early on Monday. Workplaces will be shut from Wednesday.
Bicycle rickshaws were allowed to operate in a last-minute government concession late on Sunday, but prices had soared to unaffordable levels, commuters said.
“I started walking at 7am. I could not get any bus or any other vehicles. I can’t afford a rickshaw ride,” Shefali Begum, 60, who was going to her daughter’s home in central Dhaka, told the AFP news agency.
Infections declined in May but started to rise again this month, sparking harsher restrictions.
The country has reported more than 880,000 infections and about 14,000 deaths, but experts say the actual numbers could be much higher due to possible underreporting.
More than two-thirds of new virus cases in Bangladesh’s capital were of the Delta variant, said a recent study by the independent Dhaka-based International Centre for Diarrhoeal Disease Research.