Andrew Bouffler has been battling heightened levels of mice on his property, 'Trigger Vale', Lockhart, in NSW's Riverina, for about 10 weeks, but he said there's been a big jump in numbers over the last month.

"Certainly for me it's at the stage where it's a major issue, any crop has to be baited otherwise the mice just eat the seed," he said.

"We're near a plague at our neck of the woods, and talking to people in the area we certainly seem to be at the upper level.

"The mice pressure would lessen if we had a good rain and good season - the crop could probably grow away from the mice - but it's struggling."

Mr Bouffler said that farmers across the area were having to dry sow crops, which meant mice could dig the seeds up before they were established.

"We're not even going to really know whether the mice have eaten the seeds until 10 days after a major rain event," he said.

"So if that happens in three weeks' time and then 10 days after that, we're still a month away from knowing what the actual damage they've done is."

IN OTHER NEWS:

The Lockhart farmer said he couldn't remember mice numbers being this high for at least 20 years.

"It's a little bit hard to not be aware that they're a problem, with a drought you can leave it in the paddock a little bit and you get some respite but mice like to follow you inside," he said.

"If you put any sort of food source around the shed, if you don't put it up on 44-drums or put it out of the way, they'll just move in like you wouldn't believe."

Trent Gooden also runs a farm near Lockhart and said he felt like he's seeing mice everywhere he turns.

"Everywhere you go or whatever you do they seem to be jumping out a vehicle," Mr Gooden said.

"I think we're a lot better off than people up north but we've still got a problem."

Mr Gooden said that thankfully he hadn't been badgered by many mice inside the house but the garage hadn't fared so well.

"They're everywhere; I'm not parking cars in there and we have to keep the roller doors open because of the smell," he said.

"Up in the other house on the property where we've got some tenants, they got into their Jeep Cherokee."

Mice have also been chewing the bottoms haybales, to the point that the stacks may topple, Mr Gooden said.

Due to high demand there is also a shortage of bait and chemicals, meaning longer wait times for farmers looking to control mice populations.

Around Rand and Corowa, also in southern NSW, there have been reports of people needing to empty and decontaminate water tanks after discovering mice in them.