With a deadline just weeks away, the European Union failed Thursday to break a hardening stalemate on whether to renew the licence for the widely-used weedkiller glyphosate, which critics fear causes cancer.

The European Commission said it fell short of the majority needed to renew the license for five years when it expires December 15, as only half of the 28 member states voted for its proposal.

"Given that a qualified majority could not be reached ... the result of the vote is 'no opinion,'" said the commission, the EU's executive and regulatory arm.

The latest result was hailed by environmental campaigners, including those who rallied outside EU headquarters to mock US agro-food giant Monsanto, the maker of the best-selling glyphosate product Roundup.

"Today we have seen that the seventh attempt of the European Commission to renew Glyphosate has failed again," said Luis Morago, Avaaz campaign director.

"Monsanto wanted 15 more years and they can't even get five."

The European Commission, which had originally recommended approving the herbicide's use for another decade, said it will now submit its proposal to an appeals committee by the end of November.