North Shore Mayor Andrew Williams says he will continue ignoring public health warnings to stay off Auckland's eastern beaches, despite the death of a fifth dog.
Scientists have discovered sea slugs containing the deadly toxin tetrodotoxin, which is believed to have caused the deaths of dogs and marine life.
Auckland Regional Council says the fifth dog died after visiting an eastern beach.
North Shore city councillor Chris Darby says the death shows how reckless the mayor is to dismiss public health warnings.
But Mr Williams says he will keep walking his dog and wants others to do the same. He is convinced that if people are responsible and keep dogs on leashes the risk is low, although he is worried too many people are letting dogs roam free.