The ban, which targets Monsanto's MON810 maize, the only genetically modified organism (GMO) currently allowed in Europe, was introduced in March after a previous moratorium was annulled by France's top court last November.
"The government is keeping its moratorium on the cultivation of GMO seeds currently authorized in the European Union," Ayrault told an environmental conference in Paris.
As Europe's largest crop-grower, France is under pressure to soften its stance on GMO crops, particularly after experts found this year there was no evidence justifying a ban.
French and European farmers have voiced fears the restrictions could make them fall behind in the competitive world grain market, and the EU said in May it was considering ordering the government to lift its moratorium.
Comment: GMOs: Myths, Falsehoods, Superstitions
The blind acceptance of GMOs as a solution to hunger is the real superstition because genetic engineering does not increase the yield of crops. It is a crude tool based on reductionist science which ignores the latest developments is the sciences of the fields of gene ecology, epigenetics and agro economy. The International Assessment of Agricultural Knowledge, Science and Technology for Development (IAASTD) carried out by 400 scientists over four years for the UN has categorically stated that the future of food security does not lie in genetic engineering. This is the largest and latest assessment of genetic engineering available from the scientific community. Genetic engineering is a sloppy technology because it is based on bad science which is reductionist and mechanistic and which fails to take into account the complexity and self organisation of living systems.
However, in a country that is fiercely protective of its agriculture, regarding it as part of its national identity, the government faces strong public resistance to GMO crops, as well as to the use of chemicals in farming.
Earlier this year a French court found Monsanto guilty of chemical poisoning after a farmer from the south-eastern town of Lyon claimed he had suffered neurological problems caused by inhaling one of the biotech giant's weedkillers.
Underscoring the sentiment, Ayrault said the government also intended to ban crop dusting, the use of aircraft to spray pesticides over wide areas, except in cases where there was no viable alternative.
The move was part of a broader plan to reduce the use of chemicals in farming, the prime minister said.
The two-day conference, which brought together NGOs, MPs, industries and consumers, is set to become an annual event as part of President Francois Hollande's plan to put the environment back at the top of the international agenda.
Opening the debates on Friday, Hollande set out an ambitious agenda, calling for deeper cuts in EU carbon dioxide emissions, and reiterating his pledge to cut the share of nuclear power in France's energy mix to 50 percent by 2025 from 75 percent at present.
New tenders for solar energy will be launched before the end of the year, and Ayrault said tenders would also be launched for two off-shore wind farms, one off France's Atlantic coast near the island of Noirmoutier, and another in the English Channel, off the coast of Treport in Normandy.
Renewable energy makes up 13 percent of France's energy mix, well below the 23-percent target set by former president Nicolas Sarkozy for 2020. Wind power lags neighbors like Germany and Spain with only 2 percent of electricity coming from it while solar power makes up less than 0.5 percent.