A Melbourne gardener has launched legal action against a global pharmaceutical giant in the first Australian case to link cancer with popular weedkiller Roundup.

Michael Ogalirolo, 54, was diagnosed in 2011 with non-Hodgkin lymphoma, after more than 18 years of exposure to glyphosate, the active component in Roundup.

Agribusiness Monsanto, which was purchased last year by German-based Bayer, has been accused in a Supreme Court writ of ignoring the carcinogenic impact of its top-selling herbicide.

“The defendant knew or ought to have known that the use of Roundup products were dangerous for the plaintiff … in particular causing DNA and chromosomal damage in human cells, cancer, kidney disease, infertility and nerve damage among other devastating illnesses.

“As such, Roundup products are dangerous to human health and unfit to be marketed and sold in commerce, particularly without proper warnings and directions,” the writ by Carbone Lawyers claims.

Mr Ogalirolo was told by doctors in February 2018 that his cancer was in remission, but he says his life remains on hold.