France's health and safety agency has decided to ban weedkillers that combine chemicals glyphosate and tallowamine due to uncertainty over possible health risks, the agency said on Friday.

The ANSES agency sent a letter this week to manufacturers informing them that it intends to withdraw the authorization for such products, Francoise Weber, ANSES' deputy director general, told Reuters.

The agency reviewed products combining glyphosate and tallowamine after conclusions published in November by the European Food Safety Agency (EFSA) suggested greater potential risks compared to glyphosate alone, she said.

Glyphosate, a common ingredient in weedkillers such as Monsanto's Roundup, has been the subject of fierce debate in the past year since it was classified as probably carcinogenic by a World Health Organisation body, and European Union countries are discussing whether or not to extend its EU-wide licence.

Monsanto said it was among companies affected by the French decision, calling the debate around glyphosate in Europe "political".