A health warning has been issued for toxic algae at Lake Forsyth, with authorities urging people to stay away from the water and keep animals clear of the area.

Health New Zealand advised the public to avoid contact with the lake until the warning is lifted.

Boiling the water will not remove the toxin and it should not be consumed at any time.

Fish and shellfish from the lake may contain concentrated toxins and should not be eaten.

If fish are consumed, the gut and liver should be removed and the flesh washed thoroughly in clean water.

A spokesperson said monitoring had identified elevated levels of toxic algae in the lake.

“People should avoid contact with the water and ensure children and dogs are kept well away from the lake edge,” the spokesperson said.

The spokesperson said toxic algae can produce harmful toxins that pose a risk to both people and animals.

“Exposure can cause skin irritation, nausea, vomiting and other symptoms. Dogs are particularly vulnerable because they are more likely to drink the water or lick algae from their fur.”