An Australian tourist hotspot has been declared a disaster area after being invaded by more than 100,000 bats.

The New South Wales town of Batemans Bay has been hit by a wave of dirt and destruction.

The noisy bats, commonly known as flying foxes, have caused power outages, kept tourists away and hit property prices in the south coast town.

"Well, I think it's a natural disaster. It's a disaster for residents, it's a disaster for the flora and fauna," said local MP Andrew Constance.

Russell Schneider, of the Flying Fox Task Force, said: 'This is the biggest, this is unprecedented. They've never been seen in these numbers.'

The bats, a protected species that cannot be culled, set up a colony in the town years ago but numbers have multiplied over time, media said.

The NSW Government pledged an additional A$1 million ($719,900) for state councils to manage problem bat colonies on Tuesday. They previously committed A$2.5 million for the "camp of unprecedented size" at Batemans Bay which has disrupted daily routines.

"Every morning, without fail, I have to wash the deck, wash the car," local resident Kent Lewis said.

Flying foxes, which disperse fruit and pollinate trees, perform a crucial role in the ecosystem.