Farmers are appealing for government funding to help them bait to reduce out-of-control mouse numbers in large tracts of regional NSW.

Farmers are begging for help to end a biblical mouse plague that has for months troubled western NSW communities still trying to recover from drought.

Mice have been running rampant through large tracts of NSW and parts of southern Queensland, destroying crops and causing significant damage to tonnes of stored hay and grain.

Torrential rain that fell across much of NSW in March was hoped to put a significant dampener on their numbers ahead of the sowing of the winter crop.

However the rain has had little impact in only a few areas, including Warren, northwest of Dubbo.

Cold weather has caused a lull in other communities in the central west.

But in most of the afflicted towns, the mice - which are able to breed from six weeks old and churn out a litter every 21 days - continue to wreak havoc unabated.

NSW Farmers are calling for help to end the plague, saying they can't rely on weather to put a stop to the pests.

Baiting to kill the mice is another expense on top of grain and productivity losses, which followed on from years of severe drought.

"In a modest 1000 hectare cropping area, it costs around $17,000 dollars for one baiting run before the crop is even planted," NSW Farmers grains committee chair Matthew Madden said.

"In many areas, farmers are already on their third or fourth baiting run with costs only adding up and no end in sight."

The outbreak also poses a significant human and animal health risk in affected communities.

NSW Health has been notified of 23 case of leptospirosis - a rare disease which can cause kidney failure and meningitis which is commonly passed on by mice - so far in 2021, compared to 11 last year.

"They are causing nightmares in the home, chewing through mattresses, spoiling food and people are waking up with them on their face," Mr Madden said.

CSIRO mice expert Steve Henry the impact - both psychological and financial - on affected communities is immeasurable.

Some farmers gave up on their summer crops and just ploughed them back in, and one he spoke to was emptying her 20 mice traps at least three times a night.

"I'm even hearing stories about local councils have trouble dealing with all of the dead mice that people are putting in their garbage bins because they're starting to make the streets smell," he told AAP.

"People are psychologically exhausted by this - the mice are just everywhere."

"Every time you want to try and get some clean linen out of the cupboard, you've got to take it out, wash it, hang it on the line, and put it on your beds straight off the clothesline because if you put it back in the linen closet the mice are going to be into it again."

"No one ever forgets living through a mouse outbreak, it is such a distressing thing."

Baiting is essential to the success of the winter crop he says, but the mice plague will eventually take care of itself.

"Mouse numbers crash when numbers are so high that disease is spreading (and) they're running out of food."

"They start to turn on themselves and they eat the sick and weak ones - they also start to turn on the babies - and then at that point the population crashes away almost overnight."