In a statement yesterday, Yellow-eyed Penguin Trust field manager David McFarlane said he saw a family walking three dogs at the Okia Reserve on Otago Peninsula on Monday.
''I was literally flabbergasted to see the dogs in the reserve, knowing they had been taken past several no-dog signs and that they were within metres of the beach where they could potentially encounter roosting or nesting yellow-eyed penguins.''
Trust general manager Sue Murray said the family was approached at the time and left the reserve without incident.
However, it was happening often enough at the reserve that it was causing ''concern''.
''Who knows what's happening when we're not there, because we're not there on a daily basis.''
She encouraged all dog walkers to consult the Dunedin City Council website about whether dogs were permitted in certain areas before walking their pets.
She did not have exact statistics, but ''more than a few'' yellow-eyed penguins had been killed by dogs in the last few years, she said.
The council was investigating the incident.
''Hoiho mainland numbers are critically low, with Okia Reserve having only four breeding pairs this season, down from a high in recent years of 16 pairs.
''Okia Reserve is a great place to go walking and biking, but dogs are strictly prohibited which is clearly signposted at the entrance gate.''
A hoiho was killed by a dog at the reserve in 2015, while last year in the Catlins and Oamaru there were several incidents of penguins being attacked by dogs, the trust's statement said.
Council compliance, animal and parking services team leader Peter Hanlin said it encouraged dog owners to be responsible and help protect native wildlife.
''Dog owners can sign up to become wildlife certified through the Doc-led Lead the Way programme, showing they follow best practice around wildlife.''
''It is an offence to take dogs into prohibited areas such as Okia Reserve. If convicted of an offence, breaching the dog control bylaw can carry a fine of up to $20,000 or an infringement notice can be issued for $300.''
