Greenpeace China announced on Wednesday that genetically modified rice "appears to have been planted and sold illegally in China for the last two years" according to its findings in central China's Hubei Province.

More alarmingly, two of the samples tested positive as Bt rice, genetically engineered to contain an inbuilt toxin.

Agricultural experts and Ministry of Agriculture officials immediately denied the Greenpeace claims and cited China's own "technical standards" for testing GM products.

But their answers do not lessen the public's worries over the safety of GM rice. The Greenpeace findings have sounded a warning bell.

Extra attention and caution is needed as far as GM rice is concerned.

Sales of GM rice seeds are strictly prohibited in China by legally-binding regulations and no GM rice has ever been approved for human consumption.

Since July 1996, the Ministry of Agriculture has promulgated a series of related regulations to provide safeguards for the research, including laboratory and field experiments, transportation and marketing of GM farm products.

So far, only GM cotton has been widely introduced into the fields of China. Some brands of GM beans, mostly from the United States, have been cleared for entry into cooking oil processing plants.

Still an un-named Agriculture Ministry official admitted that GM rice has been planted on a limited scale, according to China Daily's report yesterday.

Such a fact alone should make the public become more vigilant about GM rice.

Rice is the most important staple crop in the world. More than half of Chinese and most of all the people in Southeast and South Asia rely on it for calories and protein. Rice flour and gruel constitute an important part of the diet for babies and the elderly in those countries.

People in favour of enhanced GM rice research argue that GM rice offers high yields and improved nutritional content to better feed the rice-eating population.

Some of them even go as far as claiming that those who call for extreme caution are anti-science. They say there is no known publicly available environmental or human food safety evaluations for any GM rice that claims it does harm.

But they may be being too smug about their "science." Other scientists have already pointed out the potential adverse effects of GM rice, especially Bt rice, on the environment and health.

For instance, it may affect butterflies and moths, infect weeds, and help insects resistant to the introduced toxin grow stronger. It could also contaminate natural genetic resources and affect long-term soil health.

Studies have shown GM maize and corn may already have led to serious environmental and health consequences and could have contaminated more natural seedlings.

Researchers in Mexico reported to a United Nations' bio-safety conference that nearly half of the maize samples collected from farming communities far from urban centres tested positive for transgenic proteins.

Clearly GM maize has in some way disrupted the local bio-diversity of traditional maize.

Meanwhile, the public must not forget that the United States had to recall one type of GM corn worth US$1 billion because it contained the Bt toxin that kills pests but may also cause allergenic reactions in humans, according to Greenpeace.

Such effects as those could also apply to GM rice, even as the public waits for the promised further investigation from Hubei provincial government to see if this is already happening.

Humankind has caused tremendous damages to the environment, our own health and bio-diversity as a result of some initial "scientific achievements."

We should learn from our past mistakes while pushing forward such advances as GM rice, before it is too late to make amends.