Farmers reporting increased mouse activity within the Tamworth and Liverpool Pains region

NSW Farmers' president and Mullaley farmer Xavier Martin said that activity is quite high in some areas.

"This is just how it started out in 2020, running into 2021," he said.

"We saw it gradually go up and then just break out completely. So, we're used to having the numbers gradually sneak up and then just explode."

Mr Martin said during the most recent sorghum harvest he had noticed mice nibbling away at crop heads.

According to the latest April report from the CRISO and Grains and Research Development Corporation, mouse activity is being found across the grain belt and is displaying in a "patchy nature".

CRISO research officer Steve Henry said normally when we begin to enter into the cooler season mice numbers tend to drop off.

"That's not the case this year," he said.

"We do have has quite a few reports of really significant numbers of mice, especially up around the Tamworth area.

"Even the NSW Farmers' Association was recently reporting that in Coonabarabran mice were flooding out onto the streets."

The NSW Farmers' Association estimates the cost of the last plague to have been upwards of a billion dollars.

Mr Martin is urging farmers to remain vigilant and take the necessary precautions to keep rodent numbers in check.

"This is definitely the time of year where they [mice] move into warm buildings," he said.

"Currently we're tracking very similarly to 2020, so what we don't want is a repeat of 2021."

The NSW Farmers Association recommends farmers and residents keep an eye on the mouse numbers, utilise chew cards, and report any incidents.