Dog owners are being warned to keep them away from beaches on Auckland's North Shore following two canine deaths in the last three weeks.
A dog died after visiting a Browns Bay beach last month, and a second death was reported on Cheltenham Beach, Devonport.
"A woman rang to say she saw her dog eating or licking something in the distance, and shortly afterwards it threw up and then died," North Shore District Council environmental health team leader Duffy Visser told NZPA.
Two other dogs were reported to have become ill, but not die.
Checks had been inconclusive as to the cause of the deaths and illnesses, Ms Visser said.
"We're advising people to keep their dogs away from the beaches for now until we find out what it is," she said.