French Environment and Energy Minister Segolene Royal symbolically removes Monsanto's Roundup weedkiller atomizers from stands as she visits a garden shop at Bonneuil-Sur-Marne near Paris, France, June 16, 2015. Royal has asked garden shops to stop over-the-counter sales of Monsanto's Roundup weedkiller as part of a wider fight against pesticides seen as potentially harmful to humans.The International Agency for Research on Cancer (IARC), part of the World Health Organization (WHO), said in March that glyphosate, the key ingredient in Monsanto's Roundup was "probably carcinogenic to humans." REUTERS/Charles Platiau

New Zealand scientists have reviewed the evidence on the weedkiller glyphosate and announced it is "unlikely" to be carcinogenic and should not be classified as a mutagen or carcinogen under the HSNO Act.

Poisons expert Dr Wayne Temple and his colleague from the National Poisons Centre, Michael Beasley, carried out the review, which was commissioned by the Environmental Protection Authority (EPA).

Glyphosate is the active ingredient in chemical company Monsanto's Roundup and underpins much of New Zealand's - and the world's - food production. It is also widely used in parks and gardens.

TOM DILLANE/STUFF Glyphosate is the active ingredient in Monsanto's Roundup and has been used in New Zealand for 40 years.

Last year the scientific community became divided over the issue, after one World Health Organisation agency said glyphosate was "probably carcinogenic to humans" but another said it was unlikely to pose any health risk to humans.

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In June this year the European Commission had to intervene to grant a reprieve to users of the chemical, after countries became locked in disagreement.

The Commission extended the approval for the popular weedkiller until the European Chemicals Agency issues its opinion on whether the chemical is hazardous. The extended approval will last until the end of 2017.

Federated Farmers president Dr William Rolleston welcomed the report, saying glyphosate was safer than other more toxic chemicals which would have to be used in its place.

He said the farming community would have been surprised if the report had found differently. Activist groups wanted to portray the chemical in a negative light.

"Monsanto is a leader in making genetically modified plants - they're bad. Monsanto makes Roundup - it's bad. It's part of a campaign to undermine the company and its products," Rolleston said.

He said the WHO agency that found glyphosate was "probably carcinogenic to humans" had identified it as "hazard" and not as a "risk".

Green MP Steffan Browning also welcomed the report, which he said showed the EPA was taking people's concern about glyphosate seriously. He is campaigning to stop its use in parks, gardens and schools.

EPA manager of hazardous substances and new organisms Asela Atapattu, said the reason behind commissioning the report was concern from several city councils about the use of glyphosate.

"Councils have options to manage weeds, what we wanted to do was to provide them with some real science," Atapattu said.

The Auckland Council has decided to review its use after a 3696-strong public petition was presented last month.

Asked why New Zealand did not carry out its own research, rather than simply review the literature, Atapattu said overseas agencies had a better ability to produce the research.

"We're also finding all the regulators are consistently coming to the same position so it shouldn't warrant us investigating further."

Dr Temple had followed international best practice in his review, so people could be confident in its findings.

It takes into account studies reviewed by the International Agency for Research on Cancer (IARC) as well as those assessed by the European Food Safety Authority (EFSA), the US Environmental Protection Agency (US EPA) and the FAO/WHO Joint Meeting on Pesticide Residues (JMPR).

Glyphosate has been approved for use in New Zealand since 1976. There are no figures for the precise volume used in New Zealand, but there are 94 trade name products registered containing the ingredient.