A health warning has been issued for the Okere Arm of Lake Rotoiti due to an increase in potentially toxic algal blooms.
This means a health warning now applies to both Okawa Bay and Okere Arm of Lake Rotoiti.
Routine monitoring results provided by the Bay of Plenty Regional Council have confirmed blooms of blue-green algae, which are potentially toxic, in these two parts of the lake.
Toi Te Ora Medical Officer of Health Dr Neil de Wet said he advised people to avoid contact with the water in those areas.
He said contact with algal blooms can cause asthma and hayfever attacks in susceptible individuals, as well as skin rashes, stomach upsets, and in some cases neurological effects such as tingling around the mouth, headaches, breathing difficulties and visual problems.
"Sampling points are limited and blooms can occur and shift quite quickly in the right conditions, so it is always a good idea when using any rivers and lakes to check the water before you get in," Dr de Wet said.