Health officials have labelled an outbreak of paralytic shellfish poisoning as the worst seen in the Bay of Plenty.
Since last Wednesday, 20 people have been poisoned by eating shellfish collected from the Bay of Plenty shoreline.
Ten were admitted for hospital care after suffering symptoms ranging from tingling around the mouth to difficulty walking. Four people remain in hospital.
The levels of toxins being reported from routine shellfish sampling, and the number and severity of cases underline that collecting shellfish from the affected area is a significant health risk.
The health warning that was issued in August remains in place.
Medical officer of health Dr Neil de Wet said people needed to heed the warning and ensure friends and visitors to the area were made aware of the risk.
"Tell your family, whanau, friends and tourists that collecting shellfish is not safe at present. If you see someone collecting shellfish remind them - we don't want anyone else in hospital this holiday.''
Dr de Wet strongly advised against the collection of shellfish from Tairua on the east coast of the Coromandel Peninsula, south to Waihi Beach and along the Bay of Plenty coast to 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 inshore islands along this coastline.
The health warning applies to all bi-valve shellfish including mussels, pipi, tuatua, cockles, oysters, scallops as well as cat's eyes and kina (sea urchin). Shellfish in the affected area should not be taken or consumed. Paua, crayfish and crabs can still be taken but as always, the gut should be removed before cooking.
Consumption of shellfish affected by the paralytic shellfish toxin can cause numbness and tingling around the mouth, face or extremities; difficulty swallowing or breathing; dizziness; double vision; and in severe cases, paralysis and respiratory failure. These symptoms usually occur within 12 hours of a person consuming affected shellfish. Anyone suffering illness after eating shellfish should seek urgent medical attention.
For up to date information on health warnings in the Bay of Plenty please visit www.ttophs.govt.nz and click on health warnings or call 0800 221 555 and select option 7 to speak to the on call health protection officer.