Prime Minister Prayut Chan-o-cha should suspend all field trials of genetically modified (GM) plants until a law on bio-safety is introduced, environmentalists say.
Kingkorn Narintarakul Na Ayutthaya, Biothai's deputy director, led six other organisations in submitting a petition to Government House.
Kingkorn: Overseas trade could suffer
Opponents of GM products in 10 other provinces including Chiang Mai, Khon Kaen, Surin, Suphanburi, Songkhla and Phatthalung also handed a similar petition into their provincial governors to coincide with the petition submitted in the capital.
Ms Kingkorn said her group did not oppose GM plant studies in laboratories.
However, if the government wanted to conduct field trials for GM plants, it should ensure they are regulated to prevent possible contamination of the environment.
"We don't want to see a recurrence of the GM contamination incident of papaya fields in Khon Kaen in 2004. No one has been held responsible for that incident. Countries in the European Union banned papaya imports from Thailand as a result,'' she said.
The Supreme Administrative Court recently cleared the Department of Agriculture of any wrongdoing in connection with the contamination of local plants by GM papaya during a field trial in Khon Kaen.
The court said the department had done everything it could to prevent such contamination.
Ms Kingkorn said Thailand could lose heavily if it pursues field trials for GM plants, as many countries had banned GM products.
The environmentalists also demanded the government impose a regulation requiring manufacturers to label GM products to protect consumers.
Biothai says 90% of soy bean sold in the country is imported from America, which is the biggest source of GM soy bean.