India's 'Aadhar' biometric database notched up one billion members on Monday out of a population of 1.2 billion, as the government sought to allay concerns about privacy breaches in the world's biggest such scheme.
The database was set up seven years ago to streamline subsidy benefit payments to millions of poor people as well as to cut fraud and wastage.
Under the Aadhar scheme, almost 93 per cent of India's adult population has now registered their fingerprints and iris signatures and been given a biometric ID, according to the government.
Information technology minister Ravi Shankar Prasad hailed it as "an instrument of good governance" at a ceremony in New Delhi marking the crossing of the one billion member mark.
Prasad said the initiative, inherited from the previous Congress government, had enabled millions to receive cash benefits directly rather than dealing with middlemen.
He said the government had saved Rs150 billion (Rs 15000 crore) on its cooking gas subsidy scheme alone by paying cash directly to biometric card holders instead of providing cylinders at subsidised rates.
He also said all adequate safeguards were in place to ensure the personal details of card holders could not be stolen or misused by authorities given access to the database.
"We have taken all measures to ensure privacy. The data will not be shared with anyone except in cases of national security," Prasad said.
His comments come after parliament passed legislation last month giving government agencies access to the database in the interests of national security.
It was passed using a loophole to circumvent the opposition in parliament, where the ruling Bharatiya Janata Party (BJP) lacks a majority in the upper house.
The bill was presented as a money bill, which does not not need to be passed in the upper house.
Internet experts have also raised fears about the safety of such a massive database, including hacking and theft of details.