In an email to bank officers and staff, he hailed their contribution in "successfully" rolling out the scheme but added a word of caution against slackening.
He said he is "delighted by the unprecedented response" the scheme has received so far as he noted that over five crore bank accounts have been opened within five weeks of the launch against a target of 7.5 crore accounts in the first year.
The Prime Minister had earlier sent an email to bank officers and staff on August 25 before launching the scheme on August 28.
"However, as we move ahead from here, the journey is bound to become more difficult and achievements harder to come by. Reaching the last few who do not have bank accounts is going to be progressively more difficult. We must not slacken our efforts in ensuring full coverage," he told the bankers.