The French government has asked the country's health watchdog to carry out a probe, possibly leading to EU intervention, after a study said genetically modified corn caused cancer in rats.
In a joint statement, Agriculture Minister Stephane Le Foll, Ecology Minister Delphine Batho and Health and Social Affairs Minister Marisol Touraine said they had asked the National Agency for Health Safety (ANSES) to investigate the finding.
"Depending on ANSES's opinion, the government will urge the European authorities to take all necessary measures to protect human and animal health," they said.
"(The measures) could go as far as invoking emergency suspension of imports of NK603 corn to Europe pending a re-examination of this product on the basis of enhanced assessment methods."
Earlier, French scientists led by Gilles-Eric Seralini at the University of Caen in Normandy said a study to be published later on Wednesday had found that rats which had been fed with NK603 corn developed tumours.
NK603 is a corn, also called maize, made by US agribusiness giant Monsanto.
It has been engineered to make it resistant to Roundup Ready, a herbicide, thus enabling farmers to douse fields with the weed-killer in a single go.
Genetically modified (GM) crops are widely grown in North America, Brazil and China but are a hot-button issue in Europe, where their introduction has been tightly constrained.
Green groups say the crops could be dangerous to health and the environment, although this claim has so far found no traction in large-scale studies.
In 2009, the European Food Safety Agency (EFA) panel on GM organisms determined that NK603 was "as safe as conventional maize".
"Maize NK603 and derived products are unlikely to have any adverse effect on human and animal health in the context of the intended uses," it said, delivering a judgement based in part on a 90-day feeding study on rats.