A $2.9 billion settlement on a Californian couple who claimed a popular weedkiller caused their cancers has prompted the Cancer Council to issue a warning to Australians who may be at risk.

RELATED: Bayer must pay $2.9bn to couple

In the third consecutive US jury verdict against Bayer, a San Francisco court found the non-Hodgkin's lymphoma suffered by both Alva and Alberta Pilliod was directly related to the prolonged use of the the giant chemical manufacturer's top-selling herbicide Roundup.

Roundup is the most widely used glyphosate weedkiller in Australia, and while cities and/or regions in more than two dozen countries have placed partial or complete bans on the use of glyphosate, its use here remains unrestricted and it can be found on the shelves of most Bunnings stores and garden centres.

The CEO of Cancer Council Australia, Professor Sanchia Aranda, said while the council relied on evidence-based research and not US legal rulings, it had accepted the findings of the World Health Organisation's cancer agency, the International Agency for Research on Cancer, that glyphosate was “probably carcinogenic in humans”.

“The current evidence suggests those who regularly work with the glyphosate may be at risk," she said.

“People should minimise the use of the product if it’s not necessary and those who do work with it should take health and safety precautions."

A protest rally against glyphosate outside Bayer's annual general meeting in Bonn, Germany, on April 26, 2019. Credit: AP

No risk finding

In 2016 the Australian Pesticides and Veterinary Medicines Authority (APVMA) conducted a review of international research into the risks associated with glyphosate.

The statutory body, which relies on funding from the chemical companies it regulates, concluded the chemical did not pose a carcinogenic risk to humans and that there were no grounds to place it under formal reconsideration.

However, a 2018 investigation by the ABC's Four Corners made allegations against the APVMA and its relationship with Monsanto, which manufactured Roundup until it was bought out by Bayer for $US63 billion last year.

Spraying glyphosate in Colombia's southern jungle to wipe out illegal crops of coca were stopped by the Colombian government in 2015. Credit: AP

As a result of the investigation, Labor's agriculture spokesman, Joel Fitzgibbon, set up a Senate inquiry to scrutinise the independence of the regulator, a move the agriculture minister David Littleproud described as a political stunt.

The inquiry's report was released in February, finding there was "no clear evidence of instances that showed undue influence or bias, or regulatory capture".

Urgent review

In the wake of Monday's US decision, the Greens say an urgent review of Australia's use of glyphosate is needed.

Victorian Greens Senator Janet Rice told 7News.com.au both major parties were sitting on their hands over the issue to protect generous political donations from agribusiness.

Chevron Right Icon 'We need an immediate science-based investigation'.

According to the Democracy for Sale website, the Coalition has received $42,540 in political donations from Bayer since the 2016 election and $171,100 over the past six years from Croplife, the agricultural chemical industry's main lobbyist.

Labor has received $105,671 in political donations from Croplife over the past six years and $42,200 from Bayer.

"It's clear from what's coming out now we need an immediate science-based investigation," she said.

"Monsanto, now Bayer, must release publicly information it is concealing about Roundup...and we seriously question the independence of the APVMA.

"The pressure is on and we can’t sit back and wait any longer. We will continue (to apply) community and political pressure."

Victorian Greens Senator Janet Rice. Credit: AAP

A spokeswoman for Littleproud said farm chemicals were regulated by the APVMA, and "not by politicians".

"The Liberal Party declares all donations as required by law," the statement said.

Fitzgibbon was unavailable for comment.

Multiple lawsuits

Bayer is currently facing more than 13,400 US lawsuits over the herbicide's alleged cancer risk.

The Pilliods with their lawyers at a news conference on May 13, 2019, in San Francisco. Credit: AP

The company, which is appealing the Pilliod decision, issued a statement on Monday saying Roundup has been used safely and successfully worldwide for over four decades.

"Regulatory authorities around the world consider glyphosate-based herbicides safe when used as directed," the statement said, pointing to the US Environmental Protection Agency's recent report that concluded the chemical posed no risk to public health if used according to the label.

Contact Kelly Burke at kelly@7news.com.au