However, most of them are not labelled as required to indicate they contain GMO, said Tran Thi My Hien, an engineer at the Standard and Quality Monitoring Centre and the lead author of the report. 

She said 34 percent of 323 samples taken from 17 markets and supermarkets consisted of GMO elements. 

They included 40 percent of corn samples, 26 percent of soybeans, 13 percent of potatoes, and 10 percent of tomatoes. 

The GMO elements in half of the corn samples and three fifths of the soybean samples that tested positive could not be identified since available testing methods lag behind GM growth, she said. 

"GMO can now be found in seeds, agricultural produce, and processed items… Relevant ministries should issue specific guidelines on sources and labels of GMO products for the sake of both manufacturers and consumers." 

VNA