A roaming cat or dog is thought to be responsible for killing at least eight kororā that have washed up dead in a Napier suburb in the past two weeks.
The kororā, or little penguins, were found along Ahuriri's Hardinge Rd and in the inner harbour area.
A statement from a Napier City Council spokesperson said post-mortem examinations had suggested predators may have been responsible, in some cases possibly a seal, but most likely a dog or cat.
Kororā are listed as "at risk" by the Department of Conservation.
Hawke's Bay Regional Council pollution response and enforcement team leader Mike Signal said it was breeding season for little penguins and there were already a number of young ones in the area.
He said dogs were a key predator to kororā.
"This is a reminder from HBRC, NCC and DoC to please keep dogs on a leash around these sensitive areas while kororā are breeding and nesting. Rogue cats have also been reported in these areas," Signal said.
National Aquarium of New Zealand general manager Rachel Haydon said roaming pets can pose risks to wildlife.
"This risk includes stress from disturbance to significant injury or tragically even death," Haydon said.
"It is up to all of us to act vigilant for the protection of those more vulnerable than ourselves, and this includes the wildlife we are privileged to live amongst."
The Department of Conservation has requested dog owners join its 'Lead The Way' campaign, which encourages owners to keep dogs on their leads when exploring beaches and coastlines in order to protect wildlife.
If an incident does occur where wildlife is injured, members of the public are encouraged to immediately contact 0800 DOC HOT (0800 362 468) for support.