Nigeria has launched a major crackdown on fake bank-account holders in a bid to reduce fraud in the banking sector.
People were asked to enroll at their local banks to have their fingerprints taken, along with a photograph of their face by the end of Friday.
Nigeria's central bank said non-registered customers would lose electronic access to their accounts.Huge sums are allegedly stolen from Nigerian banks as a result of forgery and illegal withdrawals.
Customers who register are issued with a unique Bank Verification Number, which is used in combination with the biometric information to confirm their identity whenever a transaction is made.
Central bank spokesman Ibrahim Mu'azu on Friday told the BBC that the exercise had been ongoing for more than two years but less than half of the 52 million account holders had registered.
He said the exercise would "safeguard depositors from fraud" and allow banks to monitor their customers and serve them effectively.
It is not clear how many people have missed the deadline but millions could be affected. As the banks are not open on Saturday and Sunday, Friday is effectively the last day people can get the number.
There was a last-minute rush in June as people tried to register, before the deadline was extended to 31 October.However, the situation appeared to be calmer on Friday.
The bank has also set up centres in Europe and America to allow Nigerians in the diaspora to register.