High mice activity has been recorded by farmers and scientists, with hot spots on the Queensland and NSW border, parts of South Australia, northern Victoria and southern NSW.
CSIRO research scientist Steve Henry has been monitoring mice numbers for the past decade.
His team recently finished seven days of monitoring across 26 sites in northern Victoria and southern NSW.
On one night he and his colleague set 130 traps, with a hit rate of 30 per cent and 35 mice caught. But just a few kilometres away only two mice were trapped.
Mr Henry said it showed just how patchy the occurrence of the rodent was.
“One paddock might have a lot of mice and another adjacent paddock might not have very many at all,” Mr Henry said.
He said so far numbers weren't looking like they would return to the plague proportions experienced in central NSW and southern Queensland earlier this year, but he urged growers to be “vigilant” before planting again.
“Numbers were really really high at the start of the spring, but they've declined slightly,” Mr Henry said.
“It's really patchy ... through September, particularly through NSW where farmers were very vigilant about baiting.”
But he's warned the rain that has been falling will have a “knock-on effect” of putting really good crops on the ground.
“There will potentially be a lot of food left behind.”
Mr Henry said wherever possible farmers should slow the headers down, to avoid food being left behind.
“The less food that gets left behind during the harvest, means less food for mice, that will potentially sustain those populations through the stubble phase and into the autumn.”
Mr Henry warned farmers needed to stay vigilant.
“With mice ... unless you are out walking through the paddocks you don't actually see those signs of activity.
“By the time farmers are seeing a few, it's almost too late.”
Bait extension welcomed
NSW Farmers has welcomed the NSW Government's decision to extend the mouse bait rebate into next year.
"With mouse numbers predicted to peak again next year, we had asked the government to extend this program and it's great to see they have listened," vice-president Xavier Martin said.
"I would encourage everyone affected by the mice this year to put in their rebate forms and get ready for another round of baiting leading into autumn."
Earlier this year NSW Farmers secured a $150 million package from the NSW Government after intense lobbying, with estimates the mouse plague would chew a billion-dollar hole in the farm gate value of winter crops.
A NSW Farmers survey found a third of respondents estimated losses between $50,000 and $150,000, with a loss of stored grain and fodder having the greatest financial impact.
For more information about the zinc phosphide rebate program, visit: www.raa.nsw.gov.au
For information about household and small business rebates, visit: www.nsw.gov.au/mice