The study claimed that rats exposed to the weedkiller Roundup (glyphosate) and/or its Round-up resistant maize, NK603, developed mammary tumours and liver and kidney damage.
The researchers said 50% of males and 70% of females died prematurely, compared with only 30% and 20% respectively in the control group.
A FSA spokesman said: “This is a complex paper and we will need time to consider the way the study was carried out, the results of the study and the way the results have been analysed for significance.
Approved GM products
“The safety of the GM maize used in this study was evaluated rigorously before it was approved in the EU. We will consider any new information or research to assess whether there may be any implications on the safety of approved GM products.”
The research was led by Professor Giles-Eric Seralini at the University of Caen.
News agency Reuters report widespread criticism of the study. One expert accused the French scientists of going on a "statistical fishing trip", it said.
No one from Monsanto was available for comment. In the past the firm has insisted its products are safe and there was no evidence of any health risk to humans or animals from consuming GM crops.