Permanent account numbers (PAN) may be phased out in the future for individuals, but such numbers may remain there for companies.
An official said there is a possibility in the future when Aadhaar card may become the sole identity card for citizens.
However, the income-tax department does not have any time frame as of now to phase out PANs.
The Finance Bill, approved by Parliament, will make Aadhaar cards mandatory for filing income tax returns and applying for permanent account number (PAN).
Replying to a debate over the finance Bill in Parliament, Finance Minister Arun Jaitley had said it might become the only identity card and may replace PAN and voter identity card in the future.
In fact, Mohammed Salim of CPI (M) had raised this issue and expressed wonder as to why Aadhaar number can't be used for all the purposes to even replace PAN.
To this, the finance minister had said, "A stage may come when unique identity card (Aadhaar) may become the sole card. There are many countries where such a situation exists. There is a social security number in America and in India it (Aadhaar) could be the counterpart."
Making Aadhaar mandatory for I-T returns would plug the loopholes of duplicate PANs used by some assessees to hide their identities.
As many as 98 per cent adults in the country have Aadhaar cards or have applied for the same and the technology should be used to curb tax evasion.
The government finds it appropriate to use Aadhaar for anti-evasion as some assessees are using five PANs each to dodge the system and evade taxes.
Bhartruhari Mahtab of Biju Janata Dal had referred to the Supreme Court's ruling last year that Aadhaar is not mandatory and wanted to know whether the government was "forcing" people to have it.
"Yes, we are," Jaitley had said, adding, "If the technology, which has a network of 1.08 billion people and all tax-paying households have it, and they give it along with their ITR, then the scope for fraud and tax evasion comes down."
Aadhaar has biometric details, so its chances of misuse become minimal, the finance minister had said.
"When the country has so much technology, and when it is being put to use, then why create such a hue and cry about it? It is an anti-evasion measure which will benefit the country. So the government considers it right to implement it," he had said.
Jaitley said the UIDAI had been conceptualised by the previous UPA dispensation and the NDA government is putting it to use with 98 per cent adults or more than 108 crore people in India having been issued Aadhaar number.