Council said on Friday afternoon monitoring had detected high levels of blue-green algae.
The detection comes as Shepparton is expected to swelter through a near 40-degree day on Saturday.
Warning signs will be positioned at major recreational areas around Kialla Lakes and will remain in place while high levels of blue-green algae are present.
Kialla Lakes will not be closed to the public.
Council recommends water users from Kialla Lakes seek an alternative water supply.
You can still sightsee and enjoy other activities at Kialla Lakes that do not involve direct contact with the water.
Council recommends people and pets do not enter the water, and people who come into contact with affected water should wash affected skin immediately in clean cold water.
People should seek alternative water supply for pets, and not use affected water for cooking, drinking, washing or showering.
Boiling the affected water will not make it safe for these purposes.
Additional information on blue-green algae can be found at Goulburn-Murray Water’s blue-green algae webpage to be informed of the risks.
Blue-green algae occurs naturally in water bodies, and contains toxins harmful to humans and animals.
Signs of algae contact are skin rashes or itchiness, sore eyes, ears and nose, or if swallowed, nausea or vomiting.
It is not possible to predict how long the algae will remain at high levels, and council is continuing to monitor the situation at Kialla Lakes.
Keep up to date with current blue-green algae warnings at www.gmwater.com.au/bluegreenalgae-alert or phone the G-MW blue-green algae hotline on (03) 5826 3785.
For more information about blue-green algae and your health, visit www.betterhealth.vic.gov.au/health/healthyliving/Harmful-algal-blooms or phone NURSE-ON-CALL on 1300 606 024.