It has been 10 years since the last substantial algal bloom was recorded for Lake Rotorua, in 2010 near Hamurana.
A small bloom was recorded near the Ohau channel in 2015.
The recent health warning for the toxic algal blooms in Lake Rotorua has reminded the community that there is still work to be done to improve the water quality.
"Unfortunately, the lake has been subject to high nutrient loads from intensive land use and sewage in the past and this legacy of pollution will take decades to recover," Bay of Plenty Regional Council Rotorua catchments manager Helen Creagh said.
"Everyone in the community needs to play their part, and that includes being mindful of how they are contributing to the water quality."