Mr Xue announced at a press conference yesterday that only 15 child workers had been found so far.

The figure was way below the estimate by Henan parents, who embarked on five rescue trips to the backwaters of Shanxi to find their missing children. They claim about 1,000 children were enslaved.

'Until now, the provincial [government] has rescued 359 migrant workers, among them 15 are children and 121 mentally retarded people,' Mr Xue said.

He said the provincial government had inspected 86,395 small coal mines, sweatshops and kilns after the exposure of the slavery scandal.

Among the 4,861 brick kilns inspected, 3,186 had operated without proper licences and approval - but Mr Xue insisted that only 17 were so-called black brick kilns, where abductions, coerced labour and child labour were found.

Among the 121 mentally retarded workers found, 76 had returned to their home provinces while the remainder, who could not identify their home addresses, were sent to government shelters in Shanxi, he said.

Vice-Minister of Labour and Social Security Sun Baoshu said a mainland-wide crackdown that ended last month found 1.5 million workers without employment contracts and 116,000 workers who were not properly paid.

The government had rescued 1,340 migrant workers who were coerced to work and 367 mentally retarded workers during the crackdown, he said.

He added that 69 people involved in Shanxi brick slavery had been charged and 60 had been sentenced.

A total of 95 cadres, all low-ranking officials, were reprimanded for dereliction of duty. Two were sacked, 24 were removed from their current posts and 19 demoted.

No senior official has been held responsible for the chronic slavery problem and the government has also tried to discredit reports that exposed the scandal.

Mr Xue said the government had tracked down the person who posted an internet plea, purportedly from 400 fathers, for the rescue of their missing children.

He said many of the parents' names were duplicated.