The potentially toxic bloom can be harmful to pets and humans alike with members of the public warned to avoid contact with water at the reservoir.

“Dogs and other domestic animals should  also be stopped from entering the water," said City of Greater Bendigo manager of environmental health and local laws, Susannah Milne.

“A lack of inflow and ongoing warm temperatures have created ideal conditions for the algal blooms. 

"Visitors to the reservoir  should obey the warning signs that are located at various points around the area and not swim or wade whilst the blooms are occurring."

Ms Milne said council would monitor the bloom closely but that they were unsure how long it would take for it to disappear.