Van Der Leden said last month's discovery by members of the public was unusual.
"Over the past decade I think it's only happened once where a Tawaki has shown up in Taranaki, but I know of one other Tawaki or Fiordland crested that showed up closer to Auckland and I believe that one was rehabilitated.
"Because it's the one penguin and it's not a hundred Tawaki showing up in the North Island it's really hard to draw any hard conclusions from, but unfortunately this penguin just seemed to draw the short straw."
Tawaki have a unique yellow crest and large beak and are usually found in the lower South Island and are one of rarest of New Zealand's mainland penguins, with just 2500-3000 breeding pairs.
Van Der Leden said penguins usually forage about 200km from their burrows.
"But Tawaki actually forage way off the South Island and they've tracked them and you can see them online, but they don't come north which is interesting, seeing as this juvenile turned up in the North Island."
She praised people who found the Tawaki for calling the 0800 DOCHOT line to alert the Department of Conservation, which then got in contact with her.
"I was able to advise them on how to manage the crowd. For instance allowing space from the land to the sea so that the penguin's pathway is not obstructed, but also obviously keeping dogs on leashes.
"Just simple bits of knowledge like that really has a huge impact on the stress levels for the animal.
"You also want to protect the community because penguins do bite and they have hooked bills for fishing so they can cause injury to people and you never know what diseases they may be carrying.
"But he community did everything right in this situation and if it had not been so sick, the penguin could have possibly been safely rehabilitated."
Van Der Leden said the penguin died while under treatment at the Wildbase national wildlife hospital at Massey University.
"Unfortunately, the exhausted penguin died at Wildbase while undergoing treatment. Wildbase vets confirmed the penguin was severely underweight and had wounds to its feet and back. A subsequent necropsy showed severe lung infection, possibly due to the long swim from Fiordland in the lower South Island."
She believed that if the penguin had not been transferred to Wildbase, it would have died in the wild without the attempted treatment, especially with the risk of off-leash dogs.