Cyanobacteria is a health hazard in several Waikato lakes. Photo: Veronika Synenko / 123RF
A health warning has been issued for a Waikato lake where there has been a significant rise in cyanobacteria levels.
Ngā Roto is the sixth Waikato lake to have a current health warning.
The region's medical officer of health, Dr Richard Vipond, said the lakes should not be used for any activity where skin will come into contact with the water or lake scum.
"Swallowing water from lakes affected by blooms should also be avoided," he added.
Cyanobacteria toxins can trigger asthma, skin rashes, stomach upsets, or neurological effects.
Dogs were particularly sensitive and should not be allowed to drink or swim in the water.
"If people do come into contact with the lake when warnings are in place, or any other lake where there are visible changes to water colour, they should shower and change their clothing as soon as possible afterwards, even if no symptoms are noticeable," Vipond said.
Ngā Roto, Te Awamutu. Photo: Waipā District Council / supplied
Ngā Roto is located north of Te Awamutu. It is a natural wetland, with a boardwalk around its perimeter and is regularly used by rowers, sailors and duck hunters, according to the Waipā District Council website.
Anyone who experiences adverse effects after being exposed should contact the Waikato Public Health Service on 07 838 2569.
The Land Air Water Aotearoa site had more information on cyanobacteria levels.
The other affected lakes were Lakes Rotoroa (Hamilton Lake), Hakanoa, Whangape, Waikare and Kainui.