The Department of Conservation (DoC) have been left "disturbed" after reports of the public handling kororā/little blue penguins in Napier and posting images on social media.
Disturbances to the animals, especially during nesting, can result in chicks being abandoned or dying.
DoC Hawke's Bay operations manager Jenny Nelson-Smith said it is "unsettling" and "unacceptable" behaviour, as well as illegal.
"Kororā are wild, living animals and it's very unsettling to hear people think wildlife is simply there for their own amusement," she said.
"They are very susceptible to disturbance by people and are also vulnerable to dogs. At this time of year birds are nesting, so any disturbance may result in chicks being abandoned or dying."
The penguins are protected under the Wildlife Act 1953, with penalties, including fines and imprisonment, for offences available.
Safely handling wildlife is a skilled task and those without training risk injuring wildlife, she added.
Nelson-Smith also warned that the birds can also behave aggressively in defence and can deliver "a good nip that could take out an eye".
The National Aquarium of New Zealand general curator Joe Walcott said it is disappointing people chose to interfere with native wildlife.
"These birds face a number of threats and this certainly will not help," he said. "Penguins come ashore to nest, if they are harassed it may lead to them abandoning the nesting site.
"Additionally there is a risk of injuring a penguin. Penguins feed on live fish and need to be in top condition to catch them, even a seemingly minor injury could lead to starvation."
The Department of Conservation thanked the person who reported the cases and encouraged the public to contact DoC's hotline if they witness people treating wildlife wrongly.
The breeding season for Hawke's Bay's endangered shorebirds has also begun, but banded dotterels, black fronted dotterels and other native river birds are threatened and declining at an "alarmingly fast" rate.
Hawke's Bay Regional Council terrestrial ecologist Keiko Hashiba said the birds have been vulnerable over the next few months.
"Because these birds evolved to defend themselves against native predators, they're great at camouflage - adults, nests, eggs and all - but pretty defenceless against introduced predators, like stoats and hedgehogs, and dogs and humans," she said.
Despite a national trend in decline, a river bird survey in 2019 showed the Tukituki and Ngaruroro rivers are the second and third highest populated rivers with banded dotterels.
Hashiba said while you might see a lot birds like banded dotterels, numbers are declining.
"You can help them by leaving your car away from river beds so you don't crush nests, following other car tracks if you do need to drive, keeping your dogs on lead, and leaving the birds alone," she added.
Biosecurity biodiversity adviser Beau Fahnle said two new community predator control projects along the Tukituki and Tūtaekurī rivers have been set up to protect native birds as they nest along the rivers.
"We're partnering with the community to protect birds like banded dotterels from predators like hedgehogs, rats, feral cats, and stoats," he said.