Some 4,000 people are taking part in the two-day survey, with enumerators heading out at dawn on Friday to start counting at watering holes and lakes commonly used by elephants.
Hundreds of conservationists decided not to take part after Wildlife Minister S M Chandrasena suggested that the results of the survey would be used to identify elephants to be domesticated.
“Calves suitable for pageants will be chosen during the elephant census, tamed and handed over to the [Buddhist] temples,” he said according to the Colombo-based Daily Mirror newspaper.
Wildlife officials have denied plans to use census data to capture wild elephants.
Sri Lanka boasted 12,000 elephants in 1900, according to officials at the Department of Wildlife Conservation. The current estimate is just 4,000.