Lurgan Park users have been complaining about the awful stench coming from the lake in recent weeks.
One woman told the MAIL that it smelled as if there was a dead body decomposing in the lake.
There have been signs up at the entrance gate to Lurgan Park about Algae Bloom.
Anglers have also voiced concern at the state of the lake and had recently called on the new council to do something about the level of pollution.
One reader said she was visiting the park with her daughter and found the odour overpowering.
“I was at the lake and the smell of the water was not good. Both me and my daughter were nearly sick with the smell of it.
“It was as if someone had died in there, that’s how bad it is,” she told the MAIL.
A spokesperson for Armagh, Banbridge and Craigavon Borough Council said: “The recently reported smell at Lurgan Park Lake is most likely due to the current algal bloom on the lake, a natural phenomenon which is beyond our control.
“The algae grow in nutrient rich water in warm weather and are encouraged by the poor quality of the water entering the lake.
“A contributing factor to the unpleasant smell may have been recent weed removal from the lake causing some methane to be released from the lake sediments.
“Northern Ireland Environment Agency are currently analysing water samples taken from the lake and the council have been working with NIEA in a project to reduce and mitigate the effects of the poor water quality. As well as improving the water quality the joint project aims to improve the biodiversity and angling in the park.”