A warning has gone out to the public in the Canterbury region advising them not to collect shellfish on the coastline between Motunau Beach and Akaroa Harbour.
Canterbury District Health Board (CDHB) Medical Officer of Health, Dr Daniel Williams says routine sample gathering of the shellfish in Sumner Beach show the shellfish have levels of Dirrahetic Shellfish poisoning.
"Anyone eating shellfish from this area is potentially at risk of illness," Dr Williams says.
Dr Williams goes on to warn that cooking the shellfish does not remove the toxin for the fish.
"Mussels, oysters, tuatua, pipi, toheroa, cockles, scallops, catseyes, kina (sea urchin) and all other bivalve shellfish should not be eaten."
Paua and crayfish are safe to eat as long as the gut is completely removed.
Symptoms include diarrhea, vomiting, nausea and abdominal cramps.
The CDHB say anyone that becomes ill after consuming shellfish from the affected areas should seek medical assistance.