The last nationwide population count was taken in 1981 and the 1991 and 2001 census were not held in the parts of the Northern Province that were under heavy influence of Tamil Tiger rebels that were fighting for a separate state until they were crushed last year.

The first census island wide is to be held in 2011. The estimated population is 21 million now.

"Lack of accurate data on population, particularly in the Northern Province, has been a hindrance in planning developmental and other projects. Even the voters' lists with the Election Commission are considered to be wide off the mark," said The Hindu newspaper.

"For instance, in the Northern Province, the percentage of voting in the April parliamentary election was below 25 per cent. The low percentage is not exactly a reflection of lack of enthusiasm as a majority of the voters on the rolls are believed to have migrated out of the province," it further said.