Chilling footage shows hundreds of rodents running free amid reports of hospital patients being bitten.
People living in New South Wales, Australia, say they are enduring their worst plague of mice "in decades".
It follows a bumper grain harvest which has seen the tiny animals grow in numbers.
Footage shows hundreds of tiny rodents swarming around a farm in the town of Gilgandra.
"At night... the ground is just moving with thousands and thousands of mice just running around" farmer Ron Mckay told the Australian Broadcasting Corporation.
Supermarkets are storing food in sealed containers and at least three patients in the local hospital have been bitten by the mice, the broadcaster said.
"You can imagine that every time you open a cupboard, every time you go to your pantry, there are mice present," said Steve Henry, a rodent expert.
"And they're eating into your food containers, they're fouling your clean linen in your linen cupboard, they're running across your bed at night."
Farmers who made hay bales for the winter expect to lose many to the fast-reproducing rodents.
Local media reported that just one pair of mice can produce on average up to 500 offspring in a season.
Intensive baiting programmes have so far had little success against the infestation, and locals are hoping for heavy rain to drown the mice in their burrows.
