Deputy Premier John Barilaro and Agriculture Minister Adam Marshall said the funds were now available for use.
The rebates are meant to cover up to 50 percent of the costs of zinc phosphide baits.
“We have made $100 million available for zinc phosphide rebates so that farmers are armed and ready if mice numbers begin to increase as we get closer to spring,” Mr Barilaro said.
“This is just one part of the NSW Government’s $150 million mice support package which includes household and small business rebates and biocontrol research, reinforcing our commitment to support primary producers and regional communities.”
Mr Marshall said zinc phosphide was the best tool available for managing the plague.
“I urge farmers to start monitoring mice numbers on their farms right now and start planning how they will manage the impacts as the population increases as we approach harvest,” he said.
NSW Farmers Association vice president Xavier Martin encouraged farmers to apply now.
Claims can be made retrospectively for baits purchased as early as February 1 this year.
“This is an opportunity to prepare for spring when mice populations are predicted to swell,” Mr Martin said.
He said the “ongoing” plague would require flexibility in support from the government.
The NSW Government had previously applied to the Australian Pesticides and Veterinary Medicines Authority for permission to use bromadiolone against the mice.
Mr Marshall said the use of the poison would be like “napalm”.
However, in June, the APVMA rejected the application, citing environmental safety concerns.
Experts had raised concerns about the danger the chemical posed to native wildlife, as anything that ate a poisoned mouse stood a high risk of secondary poisoning.
The mouse plague is estimated to have caused more than $1 billion in damage to crops.
Eligible farmers can find out more about how to secure their rebate on the Rural Assistance Authority web page.