BEIJING — Thousands of children are being sold “like cabbages” to China’s booming factories as virtual slave labor.

Young people, some younger than 10, are said to have been discovered being bought and sold at a street market in one of rural China’s most overpopulated provinces, Sichuan.

According to investigative reporters, the children stood in line as they were assessed like cattle, before being driven to factories in China’s manufacturing heartland, the Pearl River Delta.

A newspaper based in the delta, Southern Metropolis Daily, suggested that abuses remain rampant in factories despite efforts by campaigners within China and abroad.

The abuses might have become worse as wages have finally begun to rise in recent years, prompting businesses to seek new ways to cut costs.

The newspaper was tipped off by residents living close to the street market. One local man said he had watched children being “sold like cabbages.”

One reporter, posing as a clothing factory manager, was allowed to inspect would-be “employees” by patting their arms and stomachs. He agreed to pay them three and a half yuan an hour — about 50 cents.

Many had fake papers saying they were older than 18; but, when asked, most said they were between 13 and 15. One was just 7, another 9.

The newspaper said many came from the same area of Sichuan, Liangshan County, where 76 children have been reported as missing since the Chinese New Year in February.

One of the most disturbing findings was that local officials seemed to be complicit. A foreman, who produced officially stamped documents concerning the children, said: “We have the complete right to manage them, by any means. You only need to sign a work agreement with us.”

The newspaper was told stories of hundreds of children being sent to electronics and toy factories across southern China.

Southern Metropolis Daily is part of the most adventurous newspaper group in China. Although run by the local government, it is encouraged to make money and breaks genuine stories to do so. Its staff have paid the price in the past, with a number of employees jailed on dubious bribery charges.

On this occasion, some of the allegations have been confirmed by the government’s central mouthpiece, the Xinhua news agency.

In a similar case last year, hundreds of young men were found to be working as slave labour in a string of brick kilns across northern China. Lured with promises of high wages, they were locked up and, in some cases, beaten to death.

According to reports from Sichuan, some of the foremen in the latest case have now been arrested and efforts are being made to return children to their parents.