TEMORA council's environment director said they are fast-tracking toxicology assessments of Lake Centenary after reports of dogs dying from suspected exposure to blue-green algae forced them to close the lake indefinitely.
The closure on Monday was effective immediately with council saying it was a precautionary step "until a thorough toxicology report on the waterbody can be carried out".
Environment director Kris Dunstan said it was the second report of a dog dying from suspected exposure to blue-green algae within the past week.
"We just got to work out what we're dealing with first and foremost," Mr Dunstan said.
"Because of the dry period, the water levels have been decreasing very rapidly.
"To be frank, we probably had only two to three weeks of water the scheme left before the lake had to be closed.
"Hopefully, we'll be much more wiser as to what's going on there perhaps by end of week."
Mr Dunstan said there are two other reports of dog deaths but they have not been confirmed.
"At the moment, all access areas including walking tracks out of bounds, but we will review once we know more," he said.
The previous time the lake had an outbreak of blue-green algae was in 2016; however, Mr Dunstan said the latest situation is more serious.
In a social media statement on Monday, the council apologised for any inconvenience caused and said it would keep the community updated.
The 55-acre man-made lake is a popular destination for recreational uses, including including fishing, water-skiing, sailing, canoeing and swimming.