The country's trademark mechanism for GM products stipulates that products containing GM ingredients should be labeled, as announced by the Ministry of Agriculture in 2001. Products that include soybeans, corn, cotton, canola or tomatoes with GM ingredients have been included in the ministry's list.

But it is hard to protect consumers' knowledge of GM food in reality, said Huang Dafang, a researcher with the Biotechnology Research Institute at the Chinese Academy of Agricultural Sciences.

"For instance, under the current label list, the product that most consumers have contact with in the domestic market is cooking oil that contains GM ingredients," he said.

"But many foods bought outside the home, such as cakes, cookies and candies as well as food in restaurants, lack clear labels even though some are made with cooking oil containing GM ingredients," he said.

His comments came after the food and drug authority in Gansu province told local markets to set up special zones for GM food starting from March 1, to guarantee consumers' right to choose what they want to buy.

All food markets in the province must establish a special counter or shelf for GM food in their stores. They are also ordered to post notices in prominent positions to tell customers they can buy GM food in special zones, according to a circular released by Gansu Food and Drug Administration on Monday.

So far, the regulation is only on trial in the province, and has not been adopted throughout the country.

"Many people now are confused due to the poor enforcement of the country's regulations on labeling GM food," said Zhang Lanzhou, an official with the administration.

Analysts believe a lack of strict management and the absence of a monitoring mechanism is largely to blame for the confusion, coupled with business concerns that labeling GM products will lower their competitiveness.

Zhao Lei, manager of a local Vanguard store in Lanzhou, said cooking oils containing GM ingredients are usually cheaper than those without.

"Sales of such GM cooking oils have declined over the past few days in the store since they have been placed away from non-GM oils," she said, without providing detailed sales information.

Wang Liping, a 44-year-old resident of Lanzhou, welcomed the move. "It will help me avoid purchasing GM food by mistake in my daily life. After all, GM food remains controversial since there is still no consensus on whether it is harmful to humans," she said.

But Shi Baozhong, a lawyer from Anhui province, said the move is only the first step in information disclosure on GM food products.

"Food vendors also have the responsibility to tell customers the differences between GM food and non-GM food they sell, which will help them have a better understanding of their food," he said.

Huang Dafang, who is also a former member of the country's biosafety committee in charge of agricultural GM organisms, said it is impossible to clearly label all food containing GM ingredients due to the lack of a cost-effective method for detecting slight amounts of GM product.