ASHULIA (AFP) - One day, Parvin was toiling to meet the fast-fashion demands of European capitals, the next she was among hundreds of thousands of Bangladeshi clothes workers made instantly jobless as the coronavirus pandemic struck.

Big-name international brands have cancelled billions of dollars in orders because of the pandemic, decimating Bangladesh's most important export industry and hurting, in particular, rural women who dominate the workforce.

Parvin, a 28-year-old seamstress, joined thousands of workers queueing to collect final wages from tables of banknotes set up at the Al Muslim factory, one of the biggest in the country that supplies some of the world's most famous labels.

The workers waited in long lines, each 1m apart in a bid to keep up social distancing, and the anxiety built as the towers of bank notes went down.

"We don't know when it will reopen," said Parvin, who collected her salary for March just before the giant complex closed its doors.

She has no other means to support her family going forward, and described her situation as a "catastrophe".

"Many factories have already closed. My husband is jobless."

Making the shirts, pullovers, bras and socks for stores in wealthier nations is the foundation of Bangladesh's impoverished economy.

It accounts for 80 per cent of the South Asian nation's US$40 billion (S$57 billion) of annual exports, and has played a vital role in its growth of the past two decades.

More than four million people, mainly women from poor rural villages, are employed in the sector.

But the industry has a reputation for running sweatshops, with workers toiling in unsafe factories without labour protections or a social safety net.

The 2013 Rana Plaza diaster, when the collapse of the garment complex claimed the lives of 1,130 people, exposed appalling safety conditions in Bangladeshi factories.

Now, with international brands walking away and a government lockdown stopping people in Bangladesh travelling, laid-off workers are complaining of being dumped without any help.

Thousands of workers - some of whom earned just US$100 a month - have staged multiple demonstrations over the past week complaining that factories have not paid them.

"Many of us don't have food at home now. We can't even ask for handouts on the streets because those poorer than us would mock us, as we have jobs," said sewing machine operator Didarul Islam.

"What do we do? Die of hunger?" added the 38-year-old father of two.

International brands have cancelled or held up orders worth US$3.11 billion, affecting more than two million workers, according to the Bangladesh Garment Manufacturers and Exporters Association (BGMEA).

"The situation is apocalyptic," said Mr Asif Ibrahim, a factory owner and a BGMEA director.

The Bangladesh group and counterparts in China, Vietnam, Pakistan, Cambodia and Myanmar, have pleaded with the high street majors not to cancel orders.

"It is time for global businesses to uphold and honour their commitment to labour rights, social responsibility and sustainable supply chains," said a joint statement.

Some of the big firms, including H&M and Inditex, which runs the Zara chain, responded by vowing not to cancel existing orders. Others have sought discounts, according to the BGMEA.

There were no promises for the future though.

H&M chief executive Helena Helmersson said that purchasing was a key area where "forceful measures" have been taken because of the pandemic.

But the situation is already dire at Ashulia, home to 600 factories where workers live in rows of concrete slums near the plants.

Mr Rubel Ahmed, the owner of a factory employing 250 people making apparel for Spanish retailers such as SDV, Ritchi and Vamutex, said he had lost more than 50 per cent of his business.

Mr Ahmed, chain smoking as he watched the empty machines in his factory, said the pandemic was "one hundred times" worse than the 2013 Rana Plaza disaster.

"Those who have smaller factories like me will be destroyed," he said.

Activist groups say action must be taken to make sure wages hold up when work starts again.

"People will remember when this crisis is over which brands stepped up to protect their workers and employees and which did not," said Mr Dominique Muller of Labour Behind the Label, a British group on workers' rights in the clothing industry.