China’s health ministry has closed 147 illegal blood collection agencies and arrested dozens of people since last May to prevent the spread of the virus that causes AIDS, the Xinhua news agency said.

The central government had told local authorities to check blood collection and supply agencies more thoroughly to prevent illegal operations from resurfacing, it reported overnight.

China had hundreds of blood collection and supply agencies, Xinhua said, without specifying how many were illegal under a law passed in August 2004 banning the buying and selling of blood.

Blood stations in China are required to test for HIV, the virus that causes AIDS.

But tens of thousands were infected with HIV in central China in the 1990s through local blood sales schemes that involved state-run health clinics, indicating a failure to properly screen donors.

The ministry had set up a national task force to ensure a secure blood supply, Deputy Health Minister Ma Xiaowei was quoted as saying on Thursday.

“Thirty people were arrested and 15 others were jailed,” Ma said, adding that another 86 blood collection agencies and more than 100 people had been punished in the crackdown.

China has been criticised for being slow to recognise its growing AIDS problem. The United Nations has said the country could have as many as 10 million cases in 2010 if the epidemic is not taken seriously.

At least 25,000 people, and perhaps as many as one million, in the central province of Henan were infected with HIV in the 1990s in blood-selling scandals that were initially covered up.

Villagers were paid to give blood that was pooled and the plasma extracted for hospitals. The remainder of the blood was then returned to donors, to avoid anaemia, meaning that one infected donor could pass the AIDS virus to the others.

China, which recently has been raising the public profile of its fight against AIDS, says it has 840,000 HIV/AIDS cases. Experts believe the figure is more likely to be between one million and 1.5 million.