WARNING signs have been erected at Craigavon Lakes
One of the warning signs close to the Watersports Centre says that high concentrations of blue-green algae have been found in the water.
It adds: “Swallowing the water or algae scum or shoreline mats can cause stomach upsets, more serious health effects and skin problems.
“It is a sensible precaution for you, your children and your animals to avoid contact with the scum, algal mats and the water close by.”
Another warning notice says you should not enter or contact the water or catch and consume fish from this lake.
It goes on: “This water contains blue green algae that may produce toxins which pose serious risk to health if contacted or ingested.
“Possible side effects include skin irritation, liver damage, nervous system damage.”
A council spokesman said: “Blue-green algae are naturally present in the majority of fresh water bodies throughout Northern Ireland for most of the year and have the potential to form blooms. With the exceptionally good weather we have been having, favourable water temperatures and the nutrients present in the water, the natural growth of blue-green algae can take place, forming algal blooms.
“Over recent days algae bloom has appeared in pockets on the Craigavon Lakes and as a result staff have erected signs for visitors to the lakes at these locations advising not to swim or to allow their dogs to swim or drink.
“Activities at Craigavon Watersports Centre have also been advised to avoid these areas.”