Australia's pesticide regulator has moved to impose new restrictions on two widely used herbicides, paraquat and diquat, after a formal regulatory review found the current approval conditions insufficient to manage risks to human health and the environment.

The Australian Pesticides and Veterinary Medicines Authority (APVMA) published the changes in its Special Gazette dated 23 June 2026, formalising restrictions that flow from an active reconsideration process the regulator has been running on both active constituents. Paraquat, in particular, has been under APVMA scrutiny over concerns spanning acute human toxicity, chronic exposure pathways, and ecotoxicological impacts.

Both compounds are bipyridylium contact herbicides. Paraquat — a non-selective knockdown herbicide long favoured in broadacre and horticultural settings — carries one of the most acute oral toxicity profiles of any registered agricultural chemical. A single small dose can cause progressive multi-organ failure for which there is no effective antidote. Diquat, structurally related, has a comparatively narrower toxicity window but shares environmental persistence concerns, particularly around aquatic systems.

Australia joins a growing cohort of jurisdictions that have revisited bipyridylium registrations in recent years. The European Union formally prohibited paraquat across member states in 2007 following European Food Safety Authority advice; Switzerland, Sri Lanka, and several Southeast Asian nations have enacted bans or severe restrictions since. The United States EPA has retained paraquat under a restricted-use classification requiring certified applicator licensing but has faced renewed domestic litigation pressure. Against that international trajectory, the APVMA's action positions Australia as tightening rather than prohibiting — a calibrated step that preserves registered uses under more stringent conditions rather than withdrawing market authorisation outright.

The regulatory mechanism here matters to practitioners. Under the Agricultural and Veterinary Chemicals Code Act 1994, the APVMA may vary, suspend, or cancel a registration at any point during a statutory review if the review generates sufficient grounds. Gazetting restrictions through a Special Gazette — rather than waiting for a final review report — signals that the authority considered the risk profile sufficient to warrant immediate interim measures rather than deferring action to the end of the full reconsideration process. Registrants and permit holders will need to reconcile existing label approvals and Material Safety Data Sheets with the incoming conditions; any off-label use that falls outside the new restrictions would constitute a breach of the Agricultural and Veterinary Chemicals Code.

For agronomists, crop consultants, and integrated weed management practitioners, the practical implications depend on exactly which use patterns the restrictions target — label claim reductions, application rate ceilings, closed-cab requirements, buffer zones, or re-entry intervals are all instruments the APVMA deploys in this context. The Special Gazette itself contains the operative text. Downstream, chemical manufacturers and distributors who hold product registrations incorporating paraquat or diquat as active constituents will face reformulation or relabelling obligations within whatever compliance window the APVMA has specified.

The broader policy context is one the regulator has navigated carefully. Paraquat's utility as a resistance-management tool — particularly in no-till and conservation tillage systems where glyphosate-resistant weed populations are now widespread — means that any functional restriction carries real agronomic cost. Grower groups and resistance-management researchers have consistently flagged the limited available substitutes for situations where a fast-acting, non-residual, soil-inactive contact herbicide is needed. That tension — between acute toxicological risk and an agronomically irreplaceable mode of action — has made the APVMA's review one of the more politically sensitive chemical reconsiderations in the current regulatory cycle.

The APVMA has not indicated a fixed timeline for completing the full paraquat review, though the 23 June gazette action suggests the authority is prepared to move incrementally as evidence warrants rather than hold all regulatory responses until a final determination. Affected registrants should treat the Special Gazette as the operative instrument and seek clarification directly from the APVMA on transition arrangements.