A health warning against collecting and eating shellfish along the Coromandel Peninsula and Bay of Plenty coastlines continues due to high levels of paralytic poison.
Toi Te Ora Public Health Services first issued a warning in December when concentration of paralytic shellfish poison (PSP) exceeded the national guideline.
Weekly testing confirmed the problem has not gone away.
"Because of the persistent high levels of toxins, the health warning advising people not to collect or consume local shellfish remains in place," Medical officer Dr Phil Shoemack said today.
The affected coastline is from Tairua Harbour on the east coast of the Coromandel Peninsula to the Bay of Plenty, including Tauranga harbour, Maketu and Waihi estuaries, eastward as far as the mouth of the Whakatane River.
The health warning applied to shellfish including mussels, pipi, tuatua, cockles, oysters, scallops, cats-eyes and kina.
The Public Health Service said paua, crayfish, and crabs can still be consumed, but the gut should be removed before cooking.
There have been no recent cases of people becoming unwell after eating affected shellfish, according to the Public Health Service.
But earlier in the year several reports were received, including two individuals who went to hospital within hours of eating contaminated shellfish.
Anyone with numbness and tingling around the mouth, or more severe neurological problems such as muscle weakness, and problems breathing should seek medical attention.
Toxin levels would be monitored weekly and the public would be advised as soon as the situation changed.