10 January, 2009 - Published 13:45 GMT
The Sri Lankan government says all its citizens must register because of what it describes as the prevailing situation in the country.
The Ministry of Defence on its website said it was taking this measure to ensure the security of the public.
"It is compulsory for all Sri Lankan citizens to register under this scheme and provisions have been made to do this in an easy harassment free way. Citizens can register simply by accessing the web site www.citizens.lk," a statement published by the Media Centre for National Security (MCNS) said.
Lakshman Hulugalle, Director General of MCNS told BBC Sandeshaya that this is not a new concept.
"When every citizen registered it is kind of a census and it is easy for the security forces to carry out random checking," he said.
Apart from those who register at police stations and internet cafes, he said, those who have internet facilities at home can register themselves online.
Critics, however, were not convinced.
An advisor to President Mahinda Rajapaksa, Vasudeva Nanayakkara, told BBC Sinhala service that the measure 'exert more pressure’ on citizens in Sri Lanka.
“This is an added harassment for the public who are already facing numerous difficulties. And I don’t think this is practically possible,” he said.
The government has in the past said rebel Tamil Tigers are using the influx of people from the north to infiltrate and plant bombs in and around the capital.
The compulsory registration comes as the Sri Lanka army continues to push into the last sections of territory held by the Tamil Tiger rebels.