Existing depositors have been given time till December 31, 2017 to provide the 12-digit unique identification number.
Ministry of Finance has issued four separate Gazette notifications making Aadhaar mandatory for opening all post office deposit accounts, Public Provident Fund (PPF), National Savings Certificate scheme and Kisan Vikas Patra deposits.
"Provided that where Aadhaar number has not been assigned, the depositor shall submit proof of application of enrolment for Aadhaar," the notification dated September 29 said.
Existing depositors who have not provided Aadhaar number at the time of application for such deposit "shall submit his Aadhaar number to the post office savings bank or deposit office concerned, on or before December 31, 2017," it added.
The government has insisted on quoting Aadhaar for bank deposits, obtaining mobile phone and several other utilities to weed out benami deals and blackmoney.
As many as 135 schemes (of 35 ministries) including the free cooking gas (LPG) to poor women, kerosene and fertiliser subsidy, targeted public distribution system (PDS) and MGNREGA will be covered by the extension.
"As a result of the review of welfare schemes covered and to provide the benefits of such schemes to all eligible beneficiaries of the scheme, it has been decided to further extend the stipulated date in all such notifications up to December 31, 2017," an order dated September 26 said.
The extension would also apply for Employees' Pension Scheme of 1995, scholarships, housing subsidy benefit, stipend to SC/ST trainees for coaching guidance and vocational training, stipend to handicapped and Aam Aadmi Bima Yojana.
Besides, it would be applicable for national apprenticeship and skill development schemes, crop insurance schemes, interest subvention scheme, scholarship and fellowship schemes, various education programmes such as mid- day meal for children and Atal Pension Yojana.
"It is hereby clarified that this extension shall only apply to those beneficiaries who are not assigned Aadhaar number or those who have not yet enrolled for Aadhaar. Such beneficiaries are required to enrol for Aadhaar by December 31, 2017 and provide their Aadhaar number or enrolment ID," it had said.
There will be no denial of services in the interim period.