As China's Communist Party congress got under way, nervous garment factory owners were on high alert, running lookouts to evade inspectors as they continued to produce coats, jackets and button-down shirts in defiance of official orders to close.

Chinese authorities have taken extraordinary measures to prevent any disturbance -- including pollution -- from marring the week-long, twice-a-decade meeting as businesses ranging from bars to factories were shut down.

Apparel producers were ordered to suspend work for the month out of fire safety concerns, but in Dahongmen, one of Beijing's last clothing manufacturing hubs, some factory owners simply took their work underground.

"I can't possibly stop for a month, so I can only choose to secretly keep on working," factory owner Yue Fang told AFP as half a dozen tailors churned out cotton-padded coats.

Yue is one of some 200 small factory owners based in Dahongmen, some 25 kilometres (16 miles) from the Great Hall of the People, where the party's top leaders are meeting to hand general secretary Xi Jinping a second term when the congress ends Tuesday.

Each factory had staff keeping an eye out for inspectors weeks before the meeting kicked off, Yue recalled.

"I didn't even dare set foot in my factory -- I just stood watch in the wind and rain" for plainclothes officials and police, she said, attaching tags to a mountain of fur-trimmed corduroy jackets in her workshop.

"It's been like World War II or something here," she said.

"As soon as the 'devils' enter the village, you quickly pull down the shutters and put out the lights. The whole town goes black and you won't find a soul on the streets," she said, using a wartime slur for Japanese invaders to refer to Communist Party inspectors.

But her business was raided a few days ago when she dropped her guard.

"They gave no explanations -- just swept through like bandits and took any clothes they saw," she said. 

- 'It's pretty terrifying' -

Zhang Jie, a 26-year-old factory owner from Hubei province, decided to give his five employees time off rather than risk reprisals. 

"As long as they don't like the look of you, they'll find some infraction. It's pretty terrifying," he said.

In Dahongmen's muddy, unpaved streets, garment industry workers lounged on damp sofas next to laundry hanging out to dry in the smoggy air, killing time. 

"We play cards, or talk about who made more money," said a 16-year-old button-hole maker surnamed Chen.

Elsewhere, a few other garment makers were also still operating on the sly.

In the nearby Daxing district, Yu Lizhan said over the sound of shears searing through silk that her company continued to cut clothes but had ceased manufacturing operations, creating a backlog.

"There's nothing we can do. If they've made a decision at the top, you can only follow along down below," Yu said as a handful of workers sliced reams of fabric. 

- No packages to Tibet -

Liu Zhixin, security guard at a Daxing clothing warehouse compound, said the inspections were not purely gratuitous, given the frequency of factory fires in the country.

"They're after these smaller companies that are messier, more chaotic, and may not have the proper licensing," he said. 

At a neighbouring warehouse, a logistics manager surnamed Chen said packages could only be sent during certain hours each day due to heightened security, slowing business.

It was also impossible during the congress to send any package to Tibet or Xinjiang -- both primarily ethnic minority regions in the far west where Chinese authorities fear threats to their rule. 

Stacking unshipped packages higher and higher, Chen said: "What does the party congress even have to do with me?"