A Florida man who authorities believe was breeding cassowaries has been killed by one of the birds.

Key points: Cassowaries are sought after in the United States by collectors of exotic birds

Cassowaries are sought after in the United States by collectors of exotic birds Florida requires owners to have a permit and "substanial experience" dealing with birds

Florida requires owners to have a permit and "substanial experience" dealing with birds It is believed the man was fatally attacked after falling over

The large, flightless birds are native to Australia and the island of New Guinea, but are sought after by collectors of exotic birds in the United States.

Regarded as the world's most dangerous bird, they stand up to 1.8 metres tall, can weigh up to 60 kilograms, and they have a 10-centimetre, dagger-like claw on each foot.

The Alachua County Fire Rescue Department told the Gainesville Sun a cassowary likely injured the man using its long claws.

He was taken to hospital where he later died.

"It looks like it was accidental. My understanding is that the gentleman was in the vicinity of the bird and at some point fell," Deputy Chief Jeff Taylor told the newspaper.

"When he fell, he was attacked."

The county sheriff's office identified the victim as Marvin Hajos, 75, and said an investigation into his death had been opened.

"Initial information indicates that this was a tragic accident for Mr Hajos," Brett Rhodenizer, a sheriff's office spokesman, told the Gainesville Sun.

"The cassowary involved remains secured on private property at this time."

In order to own a cassowary, the Florida Fish and Wildlife Conservation Commission requires a person to obtain a permit, have "substantial experience", and have a cage meeting specific requirements.

Florida Fish and Water spokeswoman Karen Parker told the Gainesville Sun the commission believed the man was breeding the birds.

ABC/AP