PARIS -- France officially imposed Saturday a ban on a strain of genetically modified (GM) corn produced by the US agribusiness giant Monsanto, with the publication of an agriculture ministry order in the state's official journal.

"The growing of corn seeds ... derived from genetically modified corn strain MON810 is prohibited on [French] territory," read the order signed by Agriculture Minister Michel Barnier.

Monsanto's 810 maize had been the only GM crop grown in France, but the French government last month began moving to ban its further use after a watchdog authority said it had "serious doubts" about the product in a report that has been controversial even among the scientists who put it together.

The agriculture ministry order said the ban would remain in force until a decision was taken whether to renew the authorization for the GM strain to be sold on the French market.

French corn farmers have already said they planned to challenge the ban in court.

With the law requiring a hearing within three weeks, corn producers could still plant the variety of GM corn this spring if France's highest administrative court supports their appeal, said Luc Esprit, director of the Association General of Corn Producers.

The association estimates that without a ban some 100,000 hectares (250,000 acres) of the GM corn would be planted this year, up from 22,000 hectares in 2007.

It estimates the ban would cause farmers losses of some 10 million euros ($15 million).

France last month invoked an EU safeguard procedure to temporarily bar Monsanto's 810 maize.

It followed a report by France's Provisional High Authority on GM Organisms that said it had "serious doubts" as to the safety of MON810.

It pointed to what it described as "a certain number of new scientific facts relating to a negative impact on flora and fauna."

Chairman Jean-Francois Le Grand, who also holds a seat in the Senate, said evidence had emerged that Mon 810 had an effect on insects, a species of earthworm and micro-organisms.

There was also concern that wind-borne pollen from MON810 could travel much further than previously thought -- perhaps as much as hundreds of miles (kilometers), said Le Grand.

The government action also followed French anti-globalization activist Jose Bove -- who has been convicted of ripping up GM crops in southern France -- launching a hunger strike to press for a year-long ban on genetically modified crops.