Pursehouse Rural Tamworth's Greg Worland said he believes there has been a reduction in mice numbers around town due to the cold weather, but the rodents are still running rampant in local paddocks.

"Every cold change and every fall of rain is certainly thinning them out a bit, but I'm still seeing lots of mice in paddocks where there is still shelter and still a food source," he said.

"They're in and out of their mouse holes, getting a bit of a feed during the day and then staying warm at night-time. There's still a fair few around but definitely had a reduction in numbers, for sure."

On Wednesday, the NSW government expanded its mouse support package, announcing an additional $100 million primary producer zinc phosphide rebate scheme.

The new support measure gives farmers a rebate of 50 per cent on zinc phosphide purchases, up to $10,000, and is back dated to January 1 and is expected to continue until December 31.

It comes after lobby group NSW Farmers and Country Women's Association called on the government to provide up to $25,000 per farm business to subsidise 50 per cent of the cost of bait products.

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Mr Worland said it's certainly welcome news, and it could encourage local producers to invest more into upfront preventative measures while numbers are lower.

"The major cost of this mouse plague isn't going to be counted in the dollars spent in mouse control, it's going to be the dollars lost in lost production with farmers losing hundreds of acres of Sorghum crop in some of the bad areas," he said.

"But it will certainly help farmers; maybe if they're standing in the paddocks scratching their heads wondering whether they can afford to bait the mice at low numbers, they might just go ahead and do it anyway.

"It's all about trying to control them at their low numbers, rather than trying to get control of them while they're out of control."

He also encouraged producers to stick to regulations set down by the Environmental Pest Managers Association (AEPMA), not only to successfully control the mice but also to protect off target species like birds and native animals.

There needs to be more education around the plague and baiting regulations, rather than just money pitched in by the government, he added.

The rebates are in addition to the $50 million package designed for households and small businesses announced last month.