A British human rights official told the United Nations today that more than 500 children were sold in Bangkok each week from April to November, and that he had bought two, for $35 for the pair.

Tim Bond, sponsored by the London-based Minority Rights Group, told a U.N. working group on slavery that he had bought two boys, ages 12 and 13, from a professional woman child-catcher who reportedly arranged the sale of more than 300 children each year.

"I bought them both for $35," he said. He then returned the boys to their homes in northeast Thailand.

"The police encourage it [child-selling,]" Bond said. "From labor shops they receive an income in return for silence, from brothels they can take their pick for free. The government prefers not to know."

Bond said the traffic in children originated in northeast Thailand, where farmers were faced with drought for six months of the year.

Meanwhile, Thailand, stung by the report, announced a major crackdown on so-called "slave factories."

Labor Department Deputy Chief Charoen Siriphan said yesterday he was moving to smash operations at a Bangkok railway station where children from the improverished northeast are allegedly auctioned.

Charoen said the Labor Department would also step up its checks of industrial plants in Bangkok and outlying areas, fining or closing down those found to be employing children under 18 without official permission.

But he cautioned the the problem would remain unsolved "as long as the government is unable to improve living conditions of the people, especially in the northeast."