Relief could be on the way for those in the midst of NSW mouse plague

Colder weather could be bringing relief for those in the middle of the mouse plague in Central West NSW.

The number of mice caught by one Dubbo farmer has reduced from thousands to just dozens.

A CSIRO survey in Parkes which captured 3000 mice found just one was pregnant.

READ MORE: Acting PM says mouse plague should be 'rehomed into inner city apartments'

It won't be clear until spring how many have been wiped out by the recent low temperatures.

It is estimated the mouse plague has cost the state's grain growers more than $1 billion in damage to winter crops.

The NSW government has announced hundreds of millions of dollars worth of support packages, including rebates for mouse baits.

There have been concerns that one bait the state government is seeking to use, bromadiolone, could pose a threat to native wildlife.

Bromadiolone is currently banned for outdoor use in Australia, and the NSW government is seeking special permission from the Australian Pesticides and Veterinary Medicines Authority.