Sampling has confirmed algal bloom in Lake Rotorua, also affecting the Ohau Channel and the Okere Arm of Lake Rotoiti, is potentially toxin-producing.
A health warning issued on Friday remains in place for Lake Rotorua, the Ohau Channel and the Okere Arm of Lake Rotoiti.
Satellite imagery and visual assessmentsby the Bay of Plenty Regional Council show an extensive algal bloom throughout much of these areas.
"The bloom on Lake Rotorua, the Ohau Channel and Okere Arm of Lake Rotoiti is blue-green algae which can be toxic and so it is important to avoid any activity which results in contact with the lake water," Medical Officer of Health for Toi Te Ora Public Health Dr Neil de Wet said today.
Contact with water affected by blooms of blue-green algae can cause asthma and hayfever attacks in some individuals.
Contact with the blue-green algae can also cause skin rashes, stomach upsets, and in some cases neurological effects such as tingling around the mouth, headaches, breathing difficulties and visual problems.
"Algal mats and scum may accumulate along the shorelines and so it's especially important that parents ensure that children avoid contact with these as they may be toxic," de Wet said.
Dogs are particularly at risk and should be kept away from the shorelines. Elsewhere in New Zealand there have been reported deaths of dogs that have eaten algae.
