Federal authorities have knocked back attempts to mitigate the NSW mouse plague through the use of super-strong mouse killer bromadiolone.
Subscribe now for unlimited access.
$0/
(min cost $0)
or signup to continue reading
The NSW government last month acquired 5000 litres of the rodent poison, considered one of the world's strongest mouse-killing chemicals.
That would have been enough to treat about 95 tonnes of grain.
However, the Australian Pesticide and Veterinary Medicines Authority on Wednesday declined to grant approval for bromadiolone's use in NSW.
Concerns have been raised over the past month that the anti-coagulant would kill not just mice but also native birds and mouse-eating animals.
APVMA chief executive officer Lisa Croft said the agency's primary concern in rejecting bromadiolone was the safety of animals that eat mice.
"Before the APVMA is able to approve any application, we must be certain that it is safe, that it will work and that it will not prevent our farmers from selling their produce overseas," Ms Croft said in a statement.
Country towns in NSW and Queensland have been struggling since last year with an infestation that has ruined crops, damaged tonnes of stored hay and grain, infiltrated homes and caused major damage.
NSW Agriculture Minister Adam Marshall said the state government was disappointed by the decision but accepted the outcome.
It would now double down on other mouse mitigation strategies.
"We didn't put all our eggs in one basket, nor have we sat on our hands while waiting for a determination," Mr Marshall said in a statement on Wednesday.
"The NSW government put $150 million on the table to give farmers rebates of 50 per cent on zinc phosphide purchases, run extensive workshops with Australia's leading mice expert and invested in Australian-leading biocontrol research to help control the plagues of the future."
Mr Marshall said the APVMA had in 2021 issued a number of emergency use permits to farmers battling the plague, expanding the use of zinc phosphide.
Farmers can also claim rebates of up to $1000 for mouse bait, traps and cleaning products, and 50 per cent of the cost of zinc phosphide baits.
Rebates for regional households and small businesses are also in place.
The mouse plague earlier this week caused the evacuation of Wellington Correctional Centre, with inmates to be transferred to other prisons.
Australian Associated Press