The first directions hearing in a class action against chemical giant Monsanto, over claims commonly used herbicide Roundup causes cancer, have been held in the Federal Court today.

Key points: It's alleged Monsanto misled consumers by suggesting Roundup's active ingredient didn't pose a health risk to humans who followed safety directions

It's alleged Monsanto misled consumers by suggesting Roundup's active ingredient didn't pose a health risk to humans who followed safety directions Lawyers say those registered for the class action developed non-Hodgkin's lymphoma, allegedly as a result of exposure to Roundup

Lawyers say those registered for the class action developed non-Hodgkin's lymphoma, allegedly as a result of exposure to Roundup German pharmaceutical company Bayer bought Monsanto last year and refutes any claims Roundup causes cancer

In the US, Monsanto was ordered to pay out hundreds of millions of dollars in damages to four cancer patients, with thousands more plaintiffs awaiting trial.

The lawyers representing the class action allege Monsanto misled consumers by suggesting the active ingredient in Roundup, glyphosate, was safe and did not pose a health risk to humans who followed the company's product safety directions.

Monsanto has repeatedly argued the science says glyphosate is safe, as do regulators across the world.

LHD Lawyers managing director Matthew Berenger said they would also allege Monsanto breached consumer product safety guarantee provisions in the Australian Consumer Law.

"At the moment, we've got 70 to 80 non-Hodgkin's lymphoma sufferers, who range from farmers to people who worked at council, to just your mum and dad, who have been using the product around the house, to hobby farmers" he said.

"The lead plaintiff formerly did weed spraying as an occupation."

'Physical, emotional and financial' toll

Lawyers allege Monsanto misled consumers by suggesting Roundup's active ingredient, glyphosate, was safe. ( AP: Haven Daley )

A second class action had also been lodged in Victoria's Supreme Court by Carbone Lawyers, with representatives attending the Federal Court hearing today.

Mr Berenger said the two parties had been encouraged to talk to each other, but no court orders were made regarding which class action would take precedence.

In a statement, LHD lawyers said those who had registered for the class action had developed non-Hodgkin's lymphoma, allegedly as a result of their exposure to Roundup in agricultural and domestic settings.

"Most group members have suffered physically, emotionally and financially as a result of their diagnosis, having been required to undergo extensive treatment programs and being left unable to work or with limited capacity," Mr Berenger said.

The lead applicant is South Australian man John Fenton who worked as a farm hand in rural Victoria, during which time he claimed he was exposed to Roundup on a regular basis.

In 2000, Mr Fenton started a contract weed-spraying business in Warrnambool Victoria, which involved hours of exposure to Roundup each week when mixing and spraying the product at various dairy farms.

He was diagnosed with non-Hodgkin's lymphoma in 2008.

"Probably, like everyone else, I saw what was happening in America and bells started ringing in my head," Mr Fenton said.

"I'm not after millions of dollars or anything, I'd just like the house back that I owned [before getting sick] and be at peace again."

German pharmaceutical company Bayer bought Monsanto last year and has continually refuted any claims Roundup caused cancer.

In a statement to the ABC, Bayer said the health and wellbeing of its consumers and the environment were critically important.

"We firmly stand behind the safety of our products, and this claim will be vigorously defended," Bayer said.

The next directions hearing is set down for February.