A United States judge rejected Bayer's $2bn class action proposal to resolve future lawsuits alleging its Roundup weedkiller causes cancer, saying in a Wednesday order that parts of the plan were "clearly unreasonable".

US District Court Judge Vince Chhabria in San Francisco said the proposal "would accomplish a lot for Monsanto", which Bayer acquired for $63bn in 2018, and "would accomplish far less for the Roundup users" who are currently healthy.

The agreement would have paused litigation linking Roundup to non-Hodgkin's lymphoma (NHL) for four years and would have barred Roundup users from seeking punitive damages once the pause on litigation expired.

In return, users could be eligible for free medical exams and compensation if they were diagnosed with non-Hodgkin's lymphoma.