Auckland beachgoers are warned to "exercise caution" as stinging bluebottles and faecal bacteria invade the region's beaches this weekend.
The SafeSwim site issued hazard alerts for the west coast beaches of Bethells Beach and Muriwai for bluebottles in the water.
Bluebottles are bright-blue creatures that float on the surface of the ocean. They are technically siphonophores - colony organisms, not jellyfish - despite their appearance.
Their venomous tentacles cause an extremely painful sting which raises red welts. These can last several days.
According to the Ministry of Heath, the best care for a sting is to flush the stung area with seawater then immerse it in heated tap water.
Serious allergic reactions are rare, however an ambulance should be called for symptoms including shortness of breath, severe dizziness or signs of shock.
Swimmers are also warned to take care over water quality issues at several beaches due to high levels of faecal contamination - exceeding national guidelines for swimming.
Water contaminated by human or animal faeces can contain disease-causing bacteria, viruses, and protozoa. Examples of these include salmonella, campylobacter, or giardia.
These can cause illnesses including gastroenteritis, respiratory illness, ear and eye infections and skin infections.
Here are the spots to avoid:
West:
Bethells Lagoon - long-term high risk
North Piha Lagoon - long-term high risk
Piha South Lagoon - long-term high risk
Fosters Bay - long-term high risk
Titirangi Beach - long-term high risk
Wood Bay - long-term high risk
Green Bay - long-term high risk
Central:
Oakley Creek - long-term high risk
Meola Reef - long-term high risk
Cox's Bay - long-term high risk
Waiheke Island:
Little Oneroa Lagoon - long-term high risk
