The public are being told to keep children and dogs away from beaches in Auckland's Hauraki Gulf while the source of a mystery toxic poison is investigated.

Barbecuing a family pet is not so very different to roasting a lamb or chook raised at home.

Tetrodotoxin found in the dead dogs' vomit and in a sea slug sample taken from Narrow Neck Beach.

An expert on sea slugs doubts they are to blame for killing dogs, saying the slugs themselves are probably victims.

Scientists have proved that slugs found on an Auckland beach are toxic but have not established what they have eaten to make them poisonous.

Test results due back today may point scientists towards the cause of the mystery illness or illnesses affecting dogs and wildlife in the Hauraki Gulf.

Personal ads for pets are taking off in NZ.