A warning has been issued to the public against collecting and consuming shellfish from the North Island's west coast because of high levels of paralytic shellfish poisoning.
The Waikato District Health Board yesterday issued a public health warning on shellfish harvested from Mohakatino in northern Taranaki to Manukau Harbour.
The warning includes Kawhia, Aotea and Raglan harbours.
Shellfish samples taken from Kawhia and Raglan had shown levels of paralytic shellfish poisoning (PSP) at 0.83 and 1.10 milligrams of toxin per kilogram of flesh. The safe limit is 0.8 milligrams per kilogram of flesh.
Anyone eating toxic shellfish was at risk of illness so kina, mussels, toheroa, pipi, tuatua, oysters, cockles and scallops from the area should be avoided, the DHB said.
Symptoms of PSP usually occurred within 12 hours of consuming shellfish and include numbness, dizziness, difficulty breathing and swallowing and, in severe cases, paralysis and respiratory failure.
Cooking shellfish does not remove the toxin.
Paua, crab and crayfish can be eaten safely only if the gut has been completely removed prior to cooking.
Consumers of shellfish from the affected areas who became ill should contact their GP immediately and keep any remaining shellfish.
Warning signs in the closure areas were being erected.
Levels of PSP at Manukau Harbour are within normal range.