A red alert has been issued for Burrendong Dam due to the presence of blue-green algae.
Water NSW urged people not to undertake recreational activities where they may come into contact with the water, including swimming or washing in the dam.
Livestock or pets should also avoid contact with the water.
Town water supplies remain unaffected and safe to drink.
ALSO MAKING NEWS:
Blue-green algae usually appear as green paint-like scums on the water, near the edges, or as greenish clumps throughout the water. It makes the water appear dirty, green or discoloured and generally has a strong musty or earthy odour.
Anyone who may have been affected by blue-green algae is advised to seek medical advice.
Updates on the blue-green algae can be obtained by calling 1800 999 457 or on the Water NSW website.