Though the system goes into operation today, an accompanying 'life card', with birth, gender, and residency data on it, will not be issued for another 12 months. More information will be added to the card in stages so that within a decade it will be a vital component of everyday Japanese life.

Critics of the numbering system argue today's launch of the system is illegal, citing a 1999 comment by the late prime minister Keizo Obuchi that 'an appropriate legal measure to protect citizens' privacy should precede the implementation of the system'.

The comment led to the government drafting and introducing a privacy protection bill, which is under Diet deliberation. But the bill's passage is considered unlikely because the legislation, ironically, has met fierce public opposition over its perceived threat to the freedom of the press.

Hiroshi Yamada, Mayor of Tokyo's Suginami Ward and a staunch opponent of the computer networking of resident registers said: 'This is not a service citizens have asked for.'

Mr Yamada argues that behind the move lurks a government plan to expand its control over citizens.

'Government agencies have an inherent desire to check up on individuals who resist government policies or who have unique opinions,' Mr Yamada said.

'With a unified code, it would be so easy for the government to collect a vast amount of data on citizens, which could be used against their interests. If we do not have people taking responsibility what awaits us is ruin.'

The government's assurances on the scheme's safety ring hollow amid recent revelations that some government agencies were engaged in background checks on 'troublesome' citizens. In June, the Self-Defence Force (SDF) admitted it surreptitiously compiled a list of people who sought information under the information disclosure law, with such notes as 'an anti-war former SDF official' and 'the mother of an unsuccessful SDF applicant'.

Later in the month, it was learned that an affiliate of the Natural Resources and Energy Agency provided local governments in 15 prefectures with nuclear plants with lists of individuals who questioned various aspects such as safety of the plants. Supporters of digitised identity claim its introduction will reduce paperwork and make bureaucrats more efficient.

The digitised strategy is officially meant to enable the government to provide more streamlined services to the public - no small boast as Japan gives the impression of striving to be the most regulated country in the developed world.

Almost every aspect of life involves reams of paperwork. Much of this requires a certified, recent copy of a person's residency registration.

The new system, its backers claim, will cut down on this tedious bureaucracy.

But the numbers do not add up for the scheme's most ardent supporter, Prime Minister Junichiro Koizumi, who faces widespread opposition to the project amid fears that it will lead to less privacy for citizens and facilitate government interference in their lives. Opinion polls consistently show that 80 per cent of the population are against the scheme and a number of municipalities have refused to sanction it.

Across the country local town and city assemblies are voting against adopting the scheme, forcing Mr Koizumi to berate them for 'trying to stop modernity'.