The gravely ill young female from Zealandia Karori Wildlife Sanctuary was found in a Kelburn gutter about a fortnight ago by two passers-by, who took her to a local vet.
The kaka was taken to the animal hospital at Wellington Zoo where she showed signs of neurological damage but no obvious injuries.
"From the clinical signs we suspected a heavy metal poisoning and she responded very well to our treatment," zoo vet Janelle Ward said.
Subsequent blood tests indicated raised zinc levels and it was assumed she had suffered zinc poisoning.
"Luckily, the X-rays showed she did not have any metal fragments in her intestinal tract."