Hunter New England Health (HNEH) has urged locals to take precautions against leptospirosis, after an increase in rats and mice due to the wet weather.

The disease is spread from animals to humans and is caused by bacteria found in infected animal urine and tissues, HNEH public health physician David Durrheim said.

"While leptospirosis is a relatively rare condition in Australia, most cases are reported from rural and regional areas, often because of mouse plagues," he said.

"Outbreaks of the disease usually occur following exposure to water, soil and mud that has been contaminated with infected animal urine, especially rodent urine.

"The bacteria can enter the body through skin cuts or abrasions, the lining of the mouth, nose, and eyes - and in rare cases through contaminated food and water."

Symptoms usually develop five to 14 days after infection and include fever, severe headache, sore muscles, chills, vomiting and red eyes.

It can be difficult to diagnose as symptoms can mimic other diseases like influenza.

Often, people with leptospirosis do not develop all the symptoms.

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In serious cases, some people may require hospitalisation if they experience kidney failure, jaundice, haemorrhaging of the skin and mucous membranes, meningitis or bleeding in the lungs, Dr Durrheim said.

People in certain jobs are at increased risk, including farmers, veterinarians and abattoir worker.

Those who enjoy outdoor activities like camping, gardening, bushwalking and water sports are at higher risk.

The public can avoid infection by washing their hands with soap, covering cuts and abrasions with waterproof dressings, wearing shoes outdoors, cleaning up rubbish and removing waste close to the home.

Contact with water or floodwater that could have been contaminated with animal urine should be avoided.

Leptospirosis is commonly treated with antibiotics such as doxycycline or penicillin, which is often most effective if started early in the disease.

NSW Health is also urging people to take care when applying rodenticides.

Before using any bait, it's vital that householders check that their product is suitable for domestic use, by reading product labels carefully.

Agricultural rodenticides can be highly toxic and cause poisoning when used incorrectly.