France has announced a ban on over the counter sales of a brand of weedkiller from garden centres after the active ingredient was classified as "probably carcinogenic to humans" by the UN.

The weedkiller is used by amateur gardeners as well as farmers and is the foremost product of American biotechnology giant Mosanto.

French Ecology Minister Segolene Royal told France 3 television on Sunday: "France must be on the offensive with regards to the banning of pesticides."

"I have asked garden centres to stop putting Monsanto's Roundup on sale" in self-service aisles, she added.

Glyphosate was introduced in the 1970s under the brand Roundup and is the most-produced weedkiller in the world, according to the IARC.

The agency's evaluation of glyphosate saw "limited evidence" of a type of cancer called non-Hodgkin lymphoma, as seen in studies in the United States, Sweden and Canada conducted among farm workers since 2001.

Monsanto strongly contested the IARC classification, commenting that "relevant, scientific data was excluded from review."

Monsanto said in a statement: "As consumers ourselves, safety is a priority for every person who works at Monsanto.

"We want to be clear: All labeled uses of glyphosate are safe for human health and supported by one of the most extensive worldwide human health databases ever compiled on an agricultural product.