This follows the recirculation of an old email about ATM security functions.
The email claims that if a person is being robbed at an ATM the police can be notified this way and that money will be dispensed while the police are on their way.
"We want to warn our customers that this 'ATM PIN reversal functionality' does not exist at Absa ATMs," Absa said on Wednesday.
"By entering your PIN number in reverse will not notify the police in any way, nor will cash be dispensed from the ATMs."
If a PIN number is entered in reverse the ATM will generate an error message and the transaction will be declined.
Three of these will result in a restriction on the account holder's card.
Absa did not know who was responsible for the email.