New Zealand Food Safety has issued a public health warning urging people not to collect or consume shellfish along the Bay of Plenty coastline, from just north of the Maketū Beach estuary to the northern end of Waihī Beach, after routine testing detected dangerous toxin levels.

Deputy director-general Vincent Arbuckle said pipi samples taken from the area showed paralytic shellfish toxin levels above the safe limit.

“Please do not gather and eat shellfish from this area because anyone doing so could get sick,” he said.

The warning covers a wide range of shellfish species, including mussels, oysters, tuatua, pipi, toheroa, cockles, scallops, pūpū (cat’s eyes) and Cook’s turban. Cooking does not remove the toxin.

Arbuckle said New Zealand Food Safety is monitoring a naturally occurring algal bloom which is spreading through the region. As shellfish filter-feed, the toxin produced by the algae accumulates in their gut and flesh.

“Generally, the more algae there are in the water, the more toxic the shellfish get,” he said.

Symptoms of paralytic shellfish poisoning can appear within 10 minutes to three hours of consumption.

They include numbness or tingling around the mouth and extremities, difficulty swallowing or breathing, dizziness, headache, nausea, vomiting, diarrhoea, paralysis and respiratory failure.

In severe cases, the illness can be fatal.

While most shellfish should be avoided, pāua, crab and crayfish remain safe to eat only if the gut is completely removed before cooking, as toxins concentrate in the gut.

Finfish are not affected, but New Zealand Food Safety advises gutting fish and discarding the liver before cooking.

No illnesses have been reported so far.

Anyone who becomes unwell after eating shellfish from the affected area should call Healthline on 0800 611 116 or seek immediate medical attention.

People are also encouraged to contact their local public health unit and keep any leftover shellfish for testing.

New Zealand Food Safety said it will continue monitoring shellfish toxin levels and will update the public as the situation changes.

There are currently no other alerts in place.

Commercially harvested shellfish – sold in shops and supermarkets or exported – is subject to strict water and flesh monitoring programmes by New Zealand Food Safety to ensure they are safe to eat.