Two of agriculture’s most widely used, and most controversial herbicides, will remain on the market, but face sweeping new restrictions after the Australian Pesticides and Veterinary Medicines Authority completed a review process that began in 1997.
The APVMA published its final decisions on paraquat and diquat last week, affirming both chemicals’ registrations while imposing significant new limits on how, where, and at what rates they can be applied.
APVMA chief executive Scott Hansen said both chemicals had been subjected to contemporary risk management frameworks and rigorous scientific investigation.
“Both chemicals remain available for use with significant new restrictions on application rates and permitted uses,” Mr Hansen said.
The most significant change is a dramatic reduction in maximum application rates.
Paraquat and diquat could previously be applied at up to 1150 grams per hectare.
Under the new rules, that ceiling drops to 231g/ha for most uses, an 80 per cent reduction.
A higher rate applies only for technology-assisted optical spot spraying, which is capped at 30 per cent of the treated area.
Backpack sprayers will be phased out entirely for both chemicals, following modelling that found they expose operators to unsafe levels, even with personal protective equipment.
Enclosed mixing and loading systems will be mandatory for all uses, a response to the risk of operators accidentally decanting concentrate into inappropriate containers, a pathway to accidental poisoning that the APVMA identified as a significant ongoing concern.
For broad scale boom spray operations, enclosed cab application will now be compulsory.
The decisions also narrow the list of situations where each chemical can lawfully be used, as well as the introduction of spray drift buffer zones.
Paraquat users applying by boom spray at standard rates must maintain a 250-metre downwind buffer from natural aquatic areas, a restriction that reflects a revised and tightened assessment of the chemical’s toxicity to aquatic species.
One of the most closely watched questions in the review was whether paraquat exposure increases the risk of Parkinson’s disease, a link that has driven bans in the European Union and dozens of other countries.
The APVMA concluded the weight of evidence does not support a direct causal association between approved use of paraquat and Parkinson’s disease risk.
The regulator received 171 submissions from scientists, doctors, farming industry groups and other stakeholders, covering a large range of impacts, such as human health, agriculture and environmental impacts.
Products bearing old labels can continue to be sold and used for two years from June 22, 2026, giving the industry time to adapt to the new conditions and source-compliant equipment.
The National Farmers’ Federation said the decision means products remain approved for use, but with lower application rates and more controls.
NFF President Hamish McIntyre said farmers take their responsibility to protect people and the environment seriously.
“Without healthy people and a healthy environment, there is no food and fibre production. That’s a fundamental reality for every farm business,” Mr McIntyre said.
“We acknowledge the community concern around paraquat, and it is absolutely critical that the products farmers use are safe for both people and the environment.”
Mr McIntyre said modern agricultural chemical use operates under strict controls.
“Today, agriculture operates under stringent regulations, including strict restrictions on application systems, mandatory personal protective equipment, and training or certification requirements for chemical use,” he said.
“These are science-based safeguards designed to protect farmers, their workers, and the environment.”
Mr McIntyre reinforced the importance of Australia’s independent regulatory system.
“Decisions about agricultural chemicals are made by the APVMA, an independent, science-based regulator that assesses the latest evidence from Australia and around the world against our unique conditions.
“Farmers rely on that independent process. We are not scientists, but we have a responsibility to follow the rules, use products correctly, and continually improve practices as new information becomes available.”
Mr McIntyre said products like paraquat have played an important role in modern farming systems.
“Paraquat helps support effective weed management and enable practices like no-till farming, which protects soil health, reduces erosion and helps retain moisture.
“These practices are critical as farmers respond to increasingly variable seasons and growing demand for food and fibre.”
Mr McIntyre said the NFF would work closely with industry following the decision.
“No one wants to see farmers put at risk, and decisions must continue to be guided by robust scientific evidence, with clear, practical and enforceable safety requirements.
“The NFF will continue to support our members with clear, evidence-based information and ensure farmers’ interests are represented as the implications of this decision are worked through.”
The full decision can be found on the APVMA website.