The City of South Perth has issued a public health warning after potentially toxic microcystis bacteria was detected at Lake Hurlingham and Lake Douglas following April rain.

“The green algae bloom, which forms a bright green surface film, is a known toxin-producing cyanobacteria,” the city’s website states.

Water Quality Australia’s website says cyanobacteria can pose a risk to livestock, wildlife, and human health.

“In severe cases, the toxins can cause damage to the liver and nervous system and there have been human deaths associated with non-routine exposure to algal toxins through dialysis,” the site states.

The Department of Health said pets could be poisoned from contact with toxic algae, which could kill them.

“Do not let your animals swim or drink in algae-affected areas. If your pet does come into contact with affected water, wash them thoroughly with fresh water before drying so they do not swallow algae while grooming their fur,” the department’s website states.

“Avoid contact with algae-affected water, particularly in areas with visible scums or discoloured water. Follow the advice on any nearby signs and keep out of the water until authorities advise the risk has passed.”

Warning signs have now been installed around both lakes, and aerators have been switched off to reduce the risk of the bacteria becoming airborne in fine droplets.

Pet owners are urged to keep animals away from the water’s edge and prevent them from swimming in, or drinking from, the lakes.

People are urged to avoid all contact with the water until further notice.

The city has confirmed it is undertaking ongoing water quality testing and will continue to monitor conditions at both locations closely.

Further updates will be provided as results become available.

For more information about the bacteria visit the Water Quality Australia website.