Lisa Argilla, a vet at Wellington Zoo, said they suspected it had suffered multiple organ failure.

BBC: Lost Antarctic penguin dies in New Zealand zoo

Argilla said the penguin weighed about 2.7 kilograms (6 pounds) when it arrived.

NPR: Penguin Found Stranded On New Zealand Beach Dies

Lisa Argilla, the veterinary science manager at the zoo, said Friday that they suspect the penguin suffered multiple organ failure.

NPR: Penguin Found Stranded On New Zealand Beach Dies

The penguin was about 1 year old, 50 centimeters (20 inches) long and its sex had not been determined, Argilla said.

NPR: Penguin Found Stranded On New Zealand Beach Dies

"As the penguin arrived nearly 3kg (6.6lb) underweight, it had absolutely no reserves and subsequently we suspect that this led to multiple organ failure, following the kidney failure diagnosed on its arrival, " Ms Argilla said.

BBC: Lost Antarctic penguin dies in New Zealand zoo

Lisa Argilla, a vet at Wellington Zoo, said the penguin had possibly struggled to find enough food or had had problems hunting and had come ashore as he needed to go through his seasonal moulting.

BBC: Lost Antarctic Royal penguin found in New Zealand