A controversial study that linked genetically modified corn to cancer in lab rats is a "scientific non-event", six French scientific academies said Friday.

"This work does not enable any reliable conclusion to be drawn," they said, adding bluntly that the affair helped "spread fear among the public."

The joint statement - an extremely rare event in French science - was signed by the national academies of agriculture, medicine, pharmacy, science, technology and veterinary studies.

It was sparked by research published in September that said rats fed with so-called NK603 corn or doses of Roundup herbicide developed tumours.

The paper, led by Gilles-Eric Seralini at the University of Caen, unleashed a storm in Europe, where GM crops are a highly sensitive issue.

Critics accused Seralini of manipulating the media to boost the impact of his findings and faulted his experiments for statistical bias.

Two fast-track official investigations into the study are to be unveiled next Monday.

The academies' statement said: "Given the numerous gaps in methods and interpretation, the data presented in this article cannot challenge previous studies which have concluded that NK603 corn is harmless from the health point of view, as are, more generally, genetically modified plants that have been authorised for consumption by animals and humans."

It dismissed the study as "a scientific non-event."

"Hyping the reputation of a scientist or a team is a serious misdemeanour when it helps to spread fear among the public that is not based on any firm conclusion," the academies said.