Potentially deadly shellfish has prompted the government to ban people from collecting in some areas near Waikato River.
The Ministry of Primary Industries said people were banned from collecting shellfish from the Waikato River mouth southwards to Papanui Point and Raglan Harbour.
Paralytic shellfish poisoning can be fatal and is caused by specific algae. Cooking the shellfish does not remove the toxin.
Mussels, oysters, tuatua, pipi, toheroa, cockles, scallops, catseyes, kina and all other bivalve shellfish can be affected.
Pāua, crab and crayfish can still be eaten if the gut has been completely removed prior to cooking.
Symptoms include numbness and a tingling around the mouth, face, and hands and feet, nausea, vomiting, leading to paralysis and death.