BEIJING, Feb. 28 (Xinhua) -- China will strengthen the supervision of the production and operation of the seed industry to prevent the use of illegal transgenic seeds, according to a work plan issued Monday by the Ministry of Agriculture and Rural Affairs.

The investigation of seed production bases and suspected seed production fields should be stricter, while the examination should be conducted before the seeds are planted, said the work plan.

Transgenic sampling inspection during seed processing and operation should be reinforced, said the document, adding that illegal acts will be punished severely.

The work plan also noted that genetically modified varieties should be strictly prevented from passing off as non-genetically modified varieties for approval.

The management of transgenic varieties such as soybean, corn and cotton should be optimized, it said.