The warning applies only to untreated water at the dam and will remain in place until monitoring and test results confirm the risk is sufficiently diminished.

People should not consume untreated water from Pindari Dam and prevent pets and livestock from entering and drinking the water.

The Severn River below Pindari Dam is on "amber alert".

Stock and domestic water users on the Severn River below the dam should apply a level of caution. They should keep a check on water supplies and discontinue using these waters if algae become present.

People should avoid recreational activities such as swimming, water skiing, canoeing and any other activity that brings them into contact with Pindari Dam until the red alert warning is lifted.

Potentially toxic blue-green algae may cause gastroenteritis if consumed, while contact can cause skin and eye irritations. Consumption of water containing algal toxins may cause liver damage and other health problems. Boiling the water does not remove algal toxins.

People should not eat mussels or crayfish from red alert warning areas. A precautionary approach to eating fin fish from red alert warning areas is advised. Any fish caught should be cleaned and washed thoroughly in uncontaminated water; the internal organs should not be eaten. Avoiding fishing during a bloom is the best way to minimise risk.

People who suspect they have been affected by blue-green algae should seek medical advice.

Blue-green algae is naturally occurring and can reproduce quickly in still or slow-flowing water when there is abundant sunlight and sufficient nutrients.

Visit the local council or local water utility websites for information about the management of blue-green algae risks in the nearby treated drinking water supplies.

Updates and information about blue-green algae blooms and red level warning areas can be obtained by visiting waternsw.com.au/algae or calling 1300 662 077.