Auckland Regional Council says it is working hard to determine what caused the deaths of four dogs on Auckland's eastern beaches but results may not be known until at least next week.
Health officials are carrying out further testing and analysis of samples.
The council says an update will be provided on Friday afternoon but it is not known when results will be released.
Public health warnings not to swim, gather shellfish or allow children on the beach remain in place.
Fish and birds have also been found dead at the beaches.