Authorities have seized a 340-kilogram alligator from a home in upstate New York where it was being kept illegally in a swimming pool. 

The home owner had built on an addition to his home and installed an in-ground swimming pool for the 3.4-metre-long reptile, and allowed children to get in the water with it.

The alligator has "blindness in both eyes" and spinal complications, among other health issues.

The owner's licence to keep the alligator expired in 2021. The state determined at that time the alligator's holding area failed to meet safety standards.

Officers took action this week after learning the "extent at which the owner was seriously endangering the public", according to a statement from New York's Department of Environmental conservation.

Owner Tony Cavallaro told the Associated Press that the alligator, Albert, had been with him since the 1990s, and promised to fight for his return.

Mr Cavallaro said he had treated the alligator like it was his child and he had never put anyone in danger.

“I’m not dangerous. I’m not being unsafe with people,” he said.

The reptile was sent to a licensed caretaker until a place could be found where it could receive permanent care, according to a release from the agency.

State environmental officials haven’t decided whether to bring charges.

AP