Potentially toxic levels of algal bloom have been found at Butchers Dam.

The Otago Regional Council’s (ORC) environmental monitoring team have collected samples from the water that show the presence of cyanobacteria, also known as toxic algae.

Further investigation shows the algal bloom is still present and appears worse than it was when it was discovered last week.

ORC is waiting for more results to confirm the alert level, but in the meantime urge people to keep out of the water.

ORC scientist, water quality and programme lead Helen Trotter said given the staff observations this week, the previous history at the site and the continuous presence of cyanobacteria scums over the past week, it was decided the warning was needed.

Warning signs have been placed in the area. PHOTO: ORC

The first week of summer and warm weather also prompted the need to issue the warning until final results are received.

The algae is potentially toxic and can be deadly to humans and animals.

Dogs should be kept on a leash to steer them away from the water and people visiting Butchers Dam for recreation should stay out of the water until it is confirmed safe to swim there.

Warning signs have been placed in the area to make visitors and residents aware of the dangers.

This summer ORC will test 33 swimming sites weekly for bacteria and 11 sites for toxic algae.

The latest water quality results are then posted to lawa.org.nz/swim  (Land Air Water Aotearoa), a resource for New Zealanders across the country to check the quality of their favourite local waterway.

To find the latest toxic algae sightings visit www.orc.govt.nz/toxicalgaesightings