A Sydney council will trial a new weed killer in a move being hailed as a "win" for more than 500 workers who walked off the job due to concerns over the use of the glyphosate-based Roundup, which has been linked to cancer.
The union representing council workers says outdoor staff at Blacktown City Council last month refused to continue using glyphosate weed killers, including Roundup, due to safety concerns.
The United Services Union claims the "dispute escalated" on Wednesday after management ordered six staff to either use the product or be forced into alternative jobs, resulting in a number of employees stopping work.
The industrial action prompted Blacktown City Council to seek an urgent hearing in the Industrial Relations Commission on Thursday morning after garbage bins weren't collected and some outdoor services were disrupted.
The council then announced on Thursday afternoon it would implement a trial of a "viable alternate weed control product".
The five-month trial will see one of the council's crews using alternate organic products while others continue to use a glyphosate-based product, the council said in a statement.
The union has hailed the decision as a "win for workers".
"Weed spraying is a common task for outdoor council staff, so it is understandable that workers have been deeply concerned by international legal cases which found a strong link between the use of glyphosate products and developing cancer," USU secretary Graeme Kelly said in a statement.
"It is unfortunate that some members of the public have been inconvenienced by this dispute, but they need to understand that workers only took the decision to stop work only after council management refused to carry out a review of safer weedkillers."
The council in a statement said it was guided by Australia's pesticides authority which states that glyphosate is safe for humans, animals and the environment and notes no regulatory agency in the world considers it to be a carcinogen.
Blacktown Mayor Stephen Bali maintained council would not place employees or the public at risk.
"Council is continually monitoring the situation and will act according to the recommendations of the regulator and on the findings that result from the trial," he said.
Bayer, which bought Roundup maker Monsanto for $US63 billion ($A90 billion) in 2018, says Roundup's active ingredient glyphosate is safe for human use and not carcinogenic.
But the company faces lawsuits by more than 13,400 plaintiffs in the US and globally and a series of Roundup jury verdicts against Bayer have prompted its share price to plummet.
Among the Australian plaintiffs is Victorian gardener Michael Ogalirolo, 54, who regularly used the herbicide between 1997 and 2018 and has developed non-Hodgkins lymphoma.
Mr Ogalirolo filed a writ in the Victorian Supreme Court in June alleging Monsanto Australia failed to warn its Roundup products were dangerous to human health.
