There has been a spike in the number of farmers reporting mice infestations, two years after a plague devastated large parts of the country's south east.
In 2021, high numbers of mice caused millions of dollars in damages.
While the numbers are not expected to get as bad this year, Xavier Martin from the New South Wales Farmers Association said memories from that event were still raw.
"The rodents' effects are fresh enough in everyone's memories, whether we're in town, in rural and regional communities, or out on farms," he said.
"We don't want to repeat what we saw this time two years ago.
"People are alert enough and aware as to how to respond to that early level of sightings and infestations."
Sightings from border to border
Mr Martin said farmers from Queensland to Victoria and west towards Adelaide had reported mouse sightings recently.
He said while there had been reports of crop losses, there were no substantial economic impacts yet.
"You can see the mice have run out of the winter crop that was left behind from the flooded harvest over summer and they've started to look for other food sources," he said.
"The summer crop's the obvious one, they're building their larder up for winter.
"If we manage them properly they won't explode into the spring, hopefully."
Catching hundreds of mice a day
David Fahey, owner of the Morundah Hotel, in the NSW Riverina, said there had been a mice infestation in the town for about three months, but it was starting to ease.
"A month ago we were catching 300 to 400 [mice] a day, cleaning up in traps, and then we had to start baiting heavily," Mr Fahey said.
"We're down to about 300 to 400 a week now."
Mr Fahey said he had been disinfecting every day and using air fresheners to get rid of the smell left by dead mice.
He hoped the cold weather would slow down breeding.
"It's just frustrating because they keep coming," he said.
"You think you've got on top of them and you get another surge; they breed pretty quick.
"Hopefully we won't get back to like we were a couple of years ago when we had millions of mice around."
Warning to farmers
The CSIRO recently visited farms in Coleambally, about 50 kilometres east of Morundah, where mice infestations were found in irrigated summer crops and maturing rice crops.
Research officer Steve Henry said it was important for farmers to know what mice numbers were like on their properties ahead of sowing, so they could make decisions about baiting.
"At sowing, mice can do a huge amount of damage if they're present in large numbers," Mr Henry said.
"But if farmers are able to spread bait straight off the back of the seeder, that gives a really good opportunity to get them knocked down as we go into winter."
Mr Martin said farmers should be alert, not alarmed.
"I'm optimistic that if people follow good science, measure the problem, and respond appropriately then we can avoid a plague," he said.
