Health warnings issued for Lake Ohakuri, Lake Maraetai and Lake Whakamaru

A health warning has been issued for Lake Whakamaru after samples taken from the lake by Waikato Regional Council confirmed a bloom of potentially toxic blue-green algae.

Today’s health warning is an update and extension of the health warning issued last week for Lake Ohakuri and Lake Maraetai.

“Members of the public should not drink any water sourced from these lakes, and should continue to avoid any activity which results in significant contact with the water,” says Dr Phil Shoemack, Medical Officer of Health.

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.

Signage has been erected at Lakes Ohakuri and Maraetai and will shortly be erected at Lake Whakamaru advising potential lake users about the algal blooms. 

Dr Shoemack advises the public to always watch out for signs of algal blooms if using lakes. Signs to look out for include discoloured water, an unusual smell, or green or brown floating algae particles.

Up-to-date information on health warnings for the Bay of Plenty and Lakes districts is available through these channels:

For information on health alerts for Waikato district, visit or contact Waikato Health Protection on 07 838 2569.

20211109 algal bloom lake whakamaru source WRC2

Image: Algal bloom at Lake Whakamaru