People have been advised to avoid collecting or eating shellfish from the Bay of Plenty coastline.
The area includes the coastline from Tairua (including Tairua Harbour) to Bowentown heads.
"Sampling confirms high levels of paralytic shellfish poison along this stretch of coast. We strongly urge people to avoid all shellfish from this area until further notice. It is unfortunate that this warning has had to be reinstated so soon, however this is a natural occurrence which is difficult to predict," Medical Officer of Health Dr Jim Miller said.
The health warning affects all bi-valve shellfish including mussels, pipi, tuatua, cockles, oysters, scallops, catseyes and kina (sea urchin). 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.