A man is fighting for his life in hospital after contracting only the fourth case in Australia of a rabies-like bat virus.

The northern NSW man was bitten by a bat "several months" ago and had received treatment for the injury.

He was confirmed on Wednesday as the first case of Australian bat lyssavirus recorded in the state.

Bat lyssavirus is transmitted from infected bats to humans when virus in their saliva enters the body through a bite or scratch.

It does not spread through the air.

It is extremely rare for the virus to transmit to humans and there is no effective treatment.

"This is a very tragic situation," Keira Glasgow, a director in health protection at NSW Health, said.

"Further investigation is underway to understand whether other exposures or factors played a role in his illness."

The virus shares similarities to rabies and has been found in species of flying foxes, fruit bats and insect-eating microbats.

In 2024, 118 people were treated after being bitten or scratched by a bat in Australia.

The 50-year-old man is the first case of the virus in NSW and the fourth in the nation.

Authorities are urging people to avoid touching or handling bats and assume they could be carrying the virus.

"If you are bitten or scratched by a bat, urgent medical assessment is crucial," Ms Glasgow said.

"You will need to wash the wound thoroughly for 15 minutes right away with soap and water and apply an antiseptic with anti-virus action, such as Betadine, and allow it to dry.

"You will then require treatment with rabies immunoglobulin and rabies vaccine."