Health officials in New South Wales have issued a bat attack alert for the Hunter region.
Extreme heat is being blamed for the flying foxes and bats becoming ill and falling from trees.
Officials say on average a person is bitten or scratched by bats every second day, which is unprecedented, with seven attacks in the last two weeks.
Most of those hurt were trying to help the bats.
Public Health Physician David Durrheim said two of the animals were infected with a virus similar to rabies.
"Two of the bats submitted for testing have actually had lyssavirus infection, so it is a real concern for us and for those people who have been exposed.
"They really are at risk of a potentially fatal infection," he said.
The heat has also caused a mass die-off of fish in the state.
Hot weather to blame
"Hot weather has resulted in some bats suffering ill health and getting caught in wires or other strange places, and people trying to assist them have unfortunately got scratched or bitten," Dr Durrheim said.
The New South Wales environment department has published guidelines on dealing with the animals in sweltering conditions.
"As flying foxes experience heat stress, they are likely to exhibit a series of behaviours indicating [the] progressive impact of that stress," the department said.
"These include clustering or clumping, panting, licking wrists and wing membranes, and descending to lower levels of vegetation or to the ground.
Good intentions could turn deadly
Doctors say the health risk potentially posed by bats cannot be ignored, as they can carry the rabies-like virus Australian bat lyssavirus (ABLV).
Doctor Durrheim said the symptoms of the bat lyssavirus were "just as awful as rabies".
"Once the disease starts it can't really be effectively treated, and almost everyone dies.
"People are actually compassionate towards these animals and don't realise that handling them can cause more harm, both for the animals and themselves."
Fiona McBurney from the group Wildlife Aid Upper Hunter said experts must be called in to deal with bats in distress.
"[It's important to] get the right people involved - our bat carers are immunised and trained to handle these bats," she said.
Heat causing mass fish die-offs in NSW
With another intense heatwave set to hit many parts of Australia this week, authorities in New South Wales are warning of more mass fish die-offs.
As many as a million fish were found dead last week along a 40km stretch of the Darling River near Broken Hill.
Primary industries minister Niall Blair said the die-off was caused by low water flows, algal blooms and high temperatures, and similar conditions were expected this week.
"Unfortunately, we are expecting that we may see more fish killed."
However, some environmentalists are attributing the mass die-off to poor water management.