The province is advising swimmers to stay away from Hillside Beach after reports of green sludge-caked waters depositing algae on its shores.

"Some species of algae can produce toxins that can be harmful to your liver or your nervous system, so when you see a dense algae bloom like the one we saw at Hillside Beach, we recommend that people don't swim," said Nicole Armstrong, the director of the province's Water Science and Management Branch.

The beach has been transformed into a green mess on the eastern shore of Lake Winnipeg. The blooms rolled in Sunday, shocking beach-goers in the area about an hour's drive north of Winnipeg.

Theresa Leathwood has been visiting the area for 30 years and was shocked to see the shore transform in just a few hours.

"I went back to my place for about an hour and when I came back out it was just gumbo. It looks like a can of green paint," she said.

It's now in the worst shape she's ever seen it and is warning people who are planning to visit to know they probably won't be able to swim.

Armstrong said staff visited the beach Monday morning.

"Some species of algae can produce toxins that can be harmful to your liver or your nervous system, so when you see a dense algae bloom like the one we saw at Hillside Beach, we recommend that people don't swim."

The province also warned pet-owners to stop pets from drinking or playing in water with thick algal blooms.