China's top health authority has ordered an investigation into an allegation that genetically modified golden rice was tested on Chinese schoolchildren in Hunan province in 2008 as part of a Sino-US research project.

"The Ministry of Health has asked the Chinese Center for Disease Control and Prevention to investigate and find out the truth as soon as possible, and inform the public of the findings," Deng Haihua, ministry spokesman said at a regular news conference on Tuesday.

"The ministry will also pay close attention to the investigation," he said.

The CDC issued a statement saying Yin Shi'an, a researcher at the institute of nutrition and food safety at the CDC, and the third author of the paper on beta-carotene in golden rice, has been suspended from his job because "his statements were inconsistent during the investigation".

In previous investigations, Yin said he was not aware of the GM rice test on the children aged 6 to 8 years old at a primary school in Hengyang, Hunan, but confirmed that he did sign a notification from The American Journal of Clinical Nutrition to approve the paper's publication.

Deng, however, declined to comment on whether the suspension meant that the Chinese institutions or researchers involved knew about the test, which they claim they were unaware of.

The environmental group Greenpeace broke the news of the controversial test in late August, saying that the joint research involved feeding golden rice, which is genetically modified to be rich in beta-carotene, to 24 children. It cited a paper published in the August edition of The American Journal of Clinical Nutrition.

The paper claimed that golden rice is effective in providing vitamin A to children. It said the partners in the study are the Zhejiang Academy of Medical Sciences, Tufts University in the US, the China CDC.

In an online statement, the Zhejiang Academy of Medical Sciences, said it cooperated with Tufts University in 2004 a study on beta-carotene in organisms, and its medical ethics panel had approved the study beforehand.

The statement claimed the programs the academy took part in did not involve GM rice, and it had no idea if the study had later tested GM rice on humans.

According to Deng, the Ministry of Health established an expert panel on medical ethics in 2000 to counsel and review major issues involving medical ethics, including studies of GM organisms.

In 2007, the ministry issued a regulation on reviewing GM studies involving humans, in which it required medical institutes to establish a panel of medical ethics to review any such studies.

The Regulation on the Safety of Agricultural Genetically Modified Organisms stipulates that studies on agricultural GM organisms in China in joint-initiatives between domestic and foreign institutions, should receive approval from the Ministry of Agriculture.

Huang Dafang, a member of the biosafety committee in charge of agricultural GM organisms, which is affiliated with the Ministry of Agriculture, told China Daily that the committee has not received any application from foreign countries to import GM crops to China for scientific research.