People have been warned against collecting and eating shellfish along the Coromandel and Bay of Plenty coastline after an outbreak of paralytic poisoning.

The area includes the coastline from Tairua south including Whiritoa, Whangamata, Onemana, and east along the Bay of Plenty coastline from Waihi Beach, including Tauranga Harbour to the mouth of the Whakatane River. All inshore islands in the area are also affected.

East from Ohope Beach the coastline is currently considered safe.

Medical officer of health Phil Shoemack told the Bay of Plenty Times sampling in the affected area had confirmed high levels of paralytic shellfish poison.

All bi-valve shellfish, including mussels, pipi, tuatua, cockles, oysters, scallops, cats-eyes and kina are covered by the warning.

The Public Health Service said paua, crayfish and crabs could still be taken, but the gut should be removed from each before cooking.

Consumption of shellfish affected by the toxin could lead to numbness and tingling around the mouth and face, difficulty swallowing or breathing, dizziness, double vision and in severe cases, paralysis and respiratory failure. The symptoms normally occurred within 12 hours of a person consuming affected shellfish.

Dr Shoemack said there was a similar problem with shellfish poison about the same time last year, and there was a greater potential risk due to the anticipated influx of holidaymakers into the area.

Toxin levels would be monitored over the holiday period, and the current warning was expected to remain in place for at least the next fortnight.