Shellfish is off the menu in the area from North Cape down to Cape Karikari in Northland after high levels of toxins have been detected.
The public health warning issued yesterday also includes shellfish from Parengarenga Houhora and Rangaunu Harbours.
The Ministry for Primary Industries advised the public not to collect or consume shellfish harvested from these areas and that cooking or freezing the shellfish did not remove the toxin.
Routine tests on shellfish samples taken from the region have shown levels of Paralytic Shellfish Poisoning (PSP) toxins above the safe limit of 0.8mg/kg set by MPI.
Officials warned anyone eating shellfish from these areas was potentially at risk of illness.
In severe cases, paralysis and respiratory failure could occur within 12 hours of consuming shellfish. Shellfish that should not be collected or eaten are mussels, oysters, tuatua, pipi, toheroa, cockles, scallops, cats eyes, kina and all other bivalve shellfish.
Pāua, crab and crayfish may still be eaten if the gut has been completely removed prior to cooking, as toxins accumulate in the gut. If the gut is not removed its contents could contaminate the meat during the cooking process.
Symptoms typically appear between 10 minutes and three hours after ingestion and may include numbness and a tingling around the mouth, face, and hands and feet.
People could experience difficulty swallowing or breathing and dizziness. Other side effects are vomiting, diarrhoea and paralysis and respiratory failure and, in severe cases, death.
If anyone becomes ill after eating shellfish from an area where a public health warning has been issued, phone Healthline for advice on 0800 61 11 16 or seek medical attention immediately.
People are advised to contact the Northland District Health Board Public Health Unit at the Whangārei Hospital on 09 4304 100 and ask to speak with the on-call Health Protection Officer. Keep any leftover shellfish in case it can be tested.