HIGH blue-green algae levels have been detected within Lake Boga and Lake Charm.

Goulburn-Murray Water issued the warnings late last week for both waterways, stating it presents a risk to the health of humans and animals.

"The algae detected are potentially toxic and may cause gastroenteritis if ingested," the alert said.

"Characteristic signs of algae contact are skin rashes or itchiness; sore eyes, ears and nose; or if swallowed, nausea or vomiting.

"The situation is being closely monitored."

Precautions were recommended, including people and pets should avoid contact with the water. People who come into contact with affected water should wash affected skin immediately in clean, cold water.

Untreated water should never be used for human consumption and boiling the affected water will not make it safe to use. Blue-green algae release toxins into the water when heated.

Stock should be kept away from recently irrigated areas for at least seven days.