Chinese authorities are sending thousands of people to rural labor camps, reviving the detention system used by the late Mao Tse-tung to silence hundreds of thousands of critics in the 1950s.

Chinese sources say the Peking police alone have dispatched more than 5,000 young people to "reeducation through labor" camps so far this year for offenses as minor as loitering or failing to have a job. The offenders are sent to the camps without trial or court review.

Former workers at such camps say that although the maximum term is now set for four years, many inmates are unable to leave at the end of their term because there is no work for them elsewhere.

The original 1957 regulation that created the camps has been widely republished in the official press and "reeducation through labor" appears to have become a major loophole in what China's post-Maoist government had claimed was a new legal system, designed to protect citizens against arbitrary arrest and confinement.

Scattered official and unofficial reports here and in the provinces suggest that the camps have been used to cripple China's tiny democracy movement of unofficial magazines and wallposters and to curb what the Chinese say is a serious problem with urban juvenile delinquency.

The editor of one unofficial magazine, Mu Changquin, committed suicide March 26 by throwing himself under a train before he and other democracy activists were about to be moved to a labor camp, according to informed Chinese sources.

One apparent way station for the youths being sent to the camps is northern Peking's Gongdelin (Virtuous Forest ) detention center, a plain, white-walled compound. It was in this area that young Chinese dissidents were detained in 1979.

Yuan Gouru, a man from Gansu Province, was detained several times in 1978 and 1979 in Peking for protesting the government's failure to compensate him for wrongs he had suffered during the Cultural Revolution of the mid-1960s.

Yuan said he protested his arrest to a supervisor at Gongdelin: "Our country's newspapers all make propaganda about the constitution and the legal system. Do you listen?"

An official named Zhang replied: "We have five teams, 1,000 policemen here. They earn their bread arresting people. The newspapers earn their living by the propaganda. Those journalists and we are trains running on different tracks."

Recent reports from Chinese and foreign sources suggest that there are many such camps in Peking's rural outskirts with thousands of inhabitants. One names Clear River Farm is thought to be located in the triangle between Peking, Tianjin and earthquake-devastated Tangshan.

A reliable Chinese source said there is another camp called Teahouse in the Peking-Tianjin-Tangshan triangle. The camp has greatly expanded in the last year with a surge of new inmates, whose average age is 23.

Labor camp guards reportedly enforce discipline by allowing some groups of prisoners to beat up others. A 1979 Peking wallposter described the alleged death of 11 inmates at a "reduction through labor" camp in Qinghai Province, in China's barren northwest region, aged 19 to 25, had displeased one of the former inmates who had remained at the camp as a worker. One of the Peking youths was then accused of a minor theft. Two days later, all the Peking inmates were herded into a compound and the doors were locked by guards. The former inmate entered the compound with several cohorts, all armed with iron bars, forks and sticks, the wallposter said.

The armed men began to beat up the Peking youths. The wallposter described the incident: "The thud of iron bars was accompanied by abuse and shreiks of pain. The victims fell on their knees to beg mercy. A strong smell of blood came from the prison. Some had their skulls split open with the brains spilling out, others had their chests perforated or their faces disfigured beyond recognition. Those who fainted were splashed with cold water and once they came to were beaten again. Prison officials watched the spectacle from the prison walls."

A young Chinese said friends of his who had spent time in the camps find it very difficult to find other work or to marry. Work units see the blemish on their record and the families of young Chinese girls and the girls themselves know that the prospects of someone so marked are not good.

A 30-year-old Chinese democracy activist said male friends of his who worked in such camps usually married women who have also been assigned to "reeducation through labor." By marrying, such couples virtually guaranteed that they would become permanent residents of the camps. They earned wages far below the minimum for such work and were allowed one leave a year to visit their families.

The August 1957 regulation creating the camps helped the late chairman Mao Tse-tung silence hundreds of thousands of people who criticized communist rule during the "Hundred Flowers" campaign, in which Mao had encouraged such criticism.

Many stayed in the camps for 20 years, until an amnesty for many of them after Mao's death. Other malcontents were added to the camps. Some, such as about 100 Chinese Jesuits, were never released.

The post-Maoist government pointedly defended the original decision to jail those who were called "rightists," and now is making use of the same regulation to solve its own problems of internal unrest.

The text of the 1957 regulation, which was reprinted this February on the front page of the People's Daily, allowed administrators to send to the camps, without court review, "people with no decent occupation, who behave like hooligans . . . counterrevolutionaries . . . not subject to criminal prosecution . . . and people who have been dismissed from government jobs, who refused to work or who willfully keep making trouble, jeopardize public affairs and refuse to mend their ways despite repeated admonitions."

The government has announced a new system for selecting inmates -- "Control Committees for Reeducation Through Labor" -- which are to be set up in all localities. Those on the committees include a mixture of police, labor and local government officials.

A recent official report from AnhuiProvince includes complaints of widespread discrimination against several reeducation inmates. The report said that the inmates had finished their terms in a local factory, but "lived in very simple shelters and received no wages other than their living expenses. iEven the color of their identification cards was different from other workers."

The report said the factory's administrators promised to end the discrimination, but officials say that the existence of such reports indicate that the practices are widespread and are likely to have a severe impact on the lives of the young people now being sent to camps.