Chinese people have been "experimented upon" over the past 10 years through unwittingly eating genetically modified rice, Greenpeace said Tuesday.

In a new report, the environmental lobby group said GM rice is being illegally sold on the Chinese mainland and accuses research institutions of playing a major role.

Last November, Greenpeace activists visited randomly chosen supermarkets and wet markets in Wuhan, capital of central China's Hubei Province, buying rice and rice products.

Tests found that four of the 15 samples were genetically modified ― including three containing a GM variety developed by Huazhong Agricultural University in Wuhan.

"Chinese people are being experimented upon and our right to know what to choose is being infringed," said Wang Jing, food and agriculture project director of Greenpeace East Asia.

"This brings huge threats to our health and environment.

Illegal trade

"Evidence shows Huazhong Agricultural University and other scientific research institutes are mainly responsible for the illegal trade in GM rice," added Wang.

Rice variety BT Shanyou 63 contains codes for a toxin in Bacillus thuringiensis (Bt) soil bacterium which makes the plant resistant to attacks by moths and butterflies.

China gave safety approval for this variety of rice in 2009 but it has not gone into commercial production, even though billions of yuan has been spent on research.

Greenpeace exposed a trade in GM rice in Hubei some 10 years ago.

In 2004, Zhang Qifa, a professor at Huazhong, admitted that a local company was selling farmers BT Shanyou 63 grown in the university's 100-hectare experimental plot.

Following the trail, Greenpeace discovered that GM rice was being illegally sold around the city.

Plowed up

After media exposure, the provincial government punished those involved and plowed up the test plot.

However, BT Shanyou 63 has still been widely found in the provinces of Hunan, Jiangxi, Zhejiang and Anhui.

And since 2006, more than 100 batches of food exported to Japan, South Korea and European Union have been found to contain BT Shanyou 63, Greenpeace said.

The green group urged the authorities to improve controls and monitoring.

China, the world's largest rice producer and consumer, has long planned to introduce GM rice. However, the public has expressed safety fears.

While genetic modification in crops can provide resistance to disease, pesticides and climatic conditions, opponents say risks have not been adequately identified.

In March last year, government scientists announced a further delay in the introduction of GM rice and corn.

"The crops have to be accepted by consumers and farmers," said Peng Yufa, a member of the GM crop biosafety committee under the Ministry of Agriculture.

Peng said that may take five years to achieve.