Bay of Plenty residents and visitors remain at risk of paralytic shellfish toxin poisoning and are being reminded not to eat any shellfish until further notice.
Toi Te Ora Public Health Service Medical Officer of Health Dr Jim Miller said levels of toxin found in shellfish were still high and two further cases of illness had been reported during the Christmas and New Year holiday.
This brings to 29 the total number of people who have been poisoned by eating toxic shellfish collected from the Bay of Plenty coastline since mid-December.
"Paralytic shellfish poisoning can be a very serious illness, it can even be fatal. People have been really sick after eating shellfish from the Bay of Plenty, with some requiring treatment in the intensive care unit.
"Please look out for the signs and don't collect or eat shellfish from the affected areas," Dr Miller said.
Shellfish should not be collected or eaten from Tairua on the east coast of the Coromandel Peninsula, south to Waihi Beach and along the Bay of Plenty coast to the Whakatane Heads in the Eastern Bay of Plenty.
The warning includes Tairua Harbour as well as Tauranga Harbour, Maketu and Waihi estuaries, Matakana and Motiti Islands, and all other islands along the coast.
The health warning applies to all bivalve shellfish including mussels, pipi, tuatua, cockles, oysters, scallops as well as cat's eyes, snails and kina (sea urchin).
Cooking or freezing the shellfish does not remove the toxin.
Paua, crayfish and crabs can still be taken but as always, the gut should be removed before consuming.
The toxin that causes the illness comes from algae in the ocean. Shellfish feed on the algae and concentrate the toxin in their flesh.
Algae levels are extremely high in the Bay at present so shellfish toxin is also at elevated levels.
Consumption of shellfish affected by the paralytic shellfish toxin can cause numbness and tingling around the mouth, face, hands and feet, difficulty swallowing or breathing, dizziness, double vision and in severe cases, paralysis and respiratory failure.
These symptoms can start as soon as one to two hours after eating toxic shellfish. Anyone becoming ill should seek urgent medical attention.