The eyewitness video obtained by Reuters showed thousands of rodents swarming around a local farm in Gilgandra.
The farming communities were hardest hit by the increase in mice. Supermarkets were storing food in sealed containers and three patients at the local hospital were bitten, Australian media reported.
Intense bait programs are attempted with little evidence of a reduction in vermin numbers, so locals hope for heavy rain to drown the mice in their burrows.
According to local media, just one pair of mice can produce up to 500 offspring on average in one season.