Three residents or patients at facilities in Tottenham, Walgett and Gulargambone received minor bites, a spokeswoman told AAP.

"The current mouse infestation across western NSW is a natural occurrence. NSW Health staff are responding with appropriate control measures," she said.

NSW Western Area Health Service has also reported a case of leptospirosis - a rare disease which can cause kidney failure and meningitis - as a result of mice in domestic dwellings.

The mice plague is not just affecting residents' health, but their livelihoods.

Farmers in many parts of regional NSW are reporting a drastic increase in mice populations, which are decimating crops, destroying stored hay and invading silos, sheds and homes.

NSW Farmers President James Jackson said grain growers hold grave concerns about the winter crop planting season, which is due to start within weeks.

"Farmers need some more control options. We are requesting that an Emergency Use Permit be issued for Zinc Phosphide to treat seed," he said on Wednesday.

NSW Farmers is also seeking some financial assistance through a small grants program.

"Mouse control is very costly," Mr Jackson said.

"Action is needed now. This mice situation is only getting worse."

Australian Associated Press