After sightings of water discolouration last Friday, samples were taken from the middle of Lake Tarawera and at Te Rata Bay near Hot Water Beach, and test results have identified blue green algae in Lake Tarawera.

Bay of Plenty Regional Council science manager Rob Donald says Lake Tarawera is at ‘amber alert' level which means the situation will continue to be monitored but no formal health warning is justified at this stage.

Lake Tarawera. Photo: Google maps.

'The blue-green algae identified are potentially toxic but the levels of algae are below health guidelines. We recommend that people do not swim in the water if it is discoloured.”

The blue-green algae have arrived recently in New Zealand and are now present in lakes throughout the North Island.

Algal blooms will cause the water to appear green and cloudy and at times the algae colonies will be visible as small green specks.

'The warmer weather and calm conditions in the lake promotes the growth of the algae. Further water samples will be taken with results expected early next week,” says Rob.