Warning signs will be positioned at recreational areas around the reservoir and remain in place while high levels of blue-green algae are present.

GMW Water Quality coordinator Bianca Atley said the reservoir would not be closed to the public and visitors could still sightsee and enjoy other activities that did not involve direct contact with the water.

"If people are near the water or on a boat, they should take care to avoid direct contact with the water," she said.

Blue-green algae occur naturally in waterbodies and contain toxins harmful to humans and animals. Characteristic signs of algae contact are skin rashes or itchiness; sore eyes, ears and nose; or if swallowed, nausea or vomiting.

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GMW recommends people and pets avoid contact with the water, and anyone who comes into contact with affected water should wash affected skin immediately in clean cold water.

Farmers should seek an alternative water supply for stock and pets where possible, and no one should use affected water for cooking, drinking, washing or showering. Boiling the affected water will not make it safe for these purposes.

A six-week-long blue-green algae warning at Laanecoorie Reservoir was removed last month, with this being ninth warning issued at the waterway in the past 20 years.

GMW says it is not possible to predict how long the algae will remain at high levels, but the authority continues to monitor the situation.

Water supplied by GMW is not suitable for human consumption without first being properly treated. Human consumption includes showering, bathing, washing, cooking, ice making and drinking.

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