The lake is still off limits after an algal outbreak earlier this month which is yet to clear.

Corangamite Shire has advised people to avoid all contact with the water, including swimming, boating, fishing and allowing pets and stock to come in contact with the water.

Testing has revealed high levels of an algae which produces toxins that can affect the function of the liver and may cause liver failure in extreme cases. Other common symptoms include skin irritations, nausea and vomiting.

The blue-green algae blooms, which have been a regular occurrence in recent summers, have had a negative effect on the town's economy as visitors are forced to travel to other lakes for boating and fishing.

Chief executive officer Andrew Mason said the shire was concerned about the problem and was now lobbying the Department of Sustainability and Environment (DSE) for funding to investigate the causes of the outbreaks and possible solutions.

Mr Mason said while the DSE managed the lake and much of the surrounding land, the shire was concerned about the significant social and economic impacts for Camperdown and Cobden in particular.

A study earlier this year showed accommodation operators appeared to be the hardest hit due to the algal outbreaks, with one business recording $5000 in lost bookings between December 24 and January 1. The retail sector was also affected with a total estimated loss of $1650 per day.

Mr Mason said Deakin University Associate Professor John Sherwood was keen to help the shire look into the problem.

"In the meantime, the key message from the Department of Health is that people shouldn't come into contact with the algae.

"We're anxious to get it resolved and will be doing ongoing monitoring," he said.

Mayor Matt Makin said while it was too late to develop any solutions to the algal outbreaks this season, the shire was encouraging anglers and water enthusiasts to use alternative waterways that had benefited from this year's above average rainfall.

Cr Makin said while it was frustrating for visitors to travel to Camperdown and find Lake Bullen Merri closed, they could consider Lake Purrumbete, Deep Lake at Derrinallum, Lismore's Lake Tooliorook and the Curdies River at Curdievale instead.

The shire has launched a marketing campaign to advise people of facilities available at nearby lakes.