Approved crops are insect-resistant, herbicide-tolerant GM corn - called Herculex I - from U.S. chemical firm Dow Chemical Co and two varieties of herbicide-tolerant GM soybeans from Franco-German pharmaceutical group Aventis SAThe number of GM plants Japan has approved for human consumption thus rises to 43 varieties of six crops-corn, soybean, sugar beet, potato, rapeseed and cotton.
Genetically modified crops contain a gene from another organism to give plants resistance to a certain herbicide or the ability to produce its own toxin to kill pests.
Critics say not enough research has been done to ensure the new technology is safe for the environment and public health.
Japan, the world's largest net importer of farm products, started importing GM crops six years ago as farmers in the United States began adopting the new technology.
To alleviate consumer concerns about the safety of GM foods, the Japanese government established in April 2001 zero tolerance for imports containing unapproved GM products and required mandatory labelling for foods containing approved GM products.
The United States, the world's biggest producer of GM crops, is the largest supplier of grains and oilseeds to Japan, which imports roughly 16 million tonnes of corn and 4.8 million tonnes of soybeans annually.