BEIJING: A Chinese journalist has uncovered the economics of China's ''huge and monstrous'' state-sanctioned abduction industry, which is designed to prevent citizens from reporting grievances to Beijing.

More than 10,000 people at a time have been engaged by municipal and county governments to ''retrieve'' citizens before they could lodge complaints at national petitions offices in Beijing, says Outlook Magazine, citing knowledgeable officials.

''In Beijing, a huge and monstrous 'grey business network' has emerged to feed, house, transport, 'man-hunt', 'detain' and retrieve petitioners,'' said the magazine, owned by China's official Xinhua news agency.

It said abuses in the quasi-commercial abduction and detention network were ''seriously damaging the Government's image''. The Government has twice this year denied such black jails exist.

On November 12, Human Rights Watch detailed how China's black jails replaced vagrant detention centres in 2003 and now constitute ''one of the most serious and widespread uses of extralegal detention in China's recent history''.

Outlook Magazine said the system peaks at times of politically sensitive events in Beijing. ''Before one important congress, an east coast province sent more than 1000 people and more than 300 cars,'' it said.

The report describes three tracks for retrieving petitioners. The first is a network of 73 local government-controlled petitioner clearing houses in Beijing, mostly residences and commercial hotels. In the second tier, detention services are outsourced to a professional security firm.

''As long as you point out anyone on the street, we help you seize and deliver them to a detention centre,'' it said, quoting the manager of a firm that services seven or eight provinces. ''You can charge 300 to 500 yuan [$47 to $79] a day from the local government and the margin goes to you,'' he said, adding that his costs were 200 yuan.

The third tier involves outsourcing to ''jobless people'' who use temporary ''black jails'' and sometimes beat or abuse their victims.

Petitions officials told the magazine their work was underpaid, dangerous and increasingly difficult because the number of petitioners had hugely risen in the past three years. ''I live every day with terror, like walking on ice,'' said an official from central China.

On November 14 the Herald reported an account of Liu Yuhong, a petitioner who had been abducted in Beijing and detained in a black jail in Tangshan municipality.

Her unborn child miscarried last month, shortly after five days of beatings and food and sleep deprivation in a Tangshan black jail. She said that Tangshan employed as many as 50 officials to retrieve petitioners from Beijing.

''The system will never stop because it is an ecology.''

Yesterday a Tangshan petitions official asked Ms Liu to take down her website account of her travails because ''it was damaging the Government's image''.