A RED alert warning has been issued for Lake Ainsworth near Lennox Head following a blue-green algae outbreak.
The North Coast Regional Algal Coordinating Committee today issued the high level alert after sampling at Lake Ainsworth recorded high levels of potentially toxic blue-green algae.
The committee warned people to not undertake recreational activities such as swimming or boating where they may be coming into direct contact with the water.
"All domestic animals should be kept away as the potential harmful effects of blue-green algae can cause death in animals," the warning read.
"Blue-green algae can be blown around the lake with the prevailing wind conditions and people are advised to avoid areas where algae is obvious (though) areas affected can change rapidly.
"Blue-green algae often appears as a green paint-like scum on the water and foreshore edges or clumps throughout the water and usually has a strong earthy odour. This makes the water appear dirty, green or discoloured. However; scums may not be present or visible, especially in windy conditions."
Warning signs have been erected in the affected areas by Ballina Shire Council.
Blue-green algae may cause severe stomach upsets, nausea and skin irritation in people and the committee warns that algae may contain toxins which cannot be removed by boiling the water.
"Common sense would suggest not to consume fish caught in water affected by a bloom," the statement continues.
"There is some evidence that small quantities of algal toxins may enter fish flesh when a bloom produces toxins.
"Any fish caught in water affected by a bloom should be cleaned and washed thoroughly in uncontaminated water and any internal organs disposed of before consumption."
Ballina Shire Council will continue to monitor the bloom and the public will be advised as the situation changes.
Information about blue-green algae blooms is available from the freecall Algal Information Hotline on 1800 999 457, or by visiting the NSW Office of Water website.
The current status of Lake Ainsworth is also available on the Ballina Shire Council website.