National Australia Bank began contacting about 13,000 customers on Friday night to advise them of a security breach involving customer names, dates of birth, contact details and in some cases, a government-issued identification number, such as driver's licence numbers.

The disclosure of the breach comes after the private details of almost 100,000 Australian bank customers were exposed in a cyber attack on the real-time payments platform PayID, which allows the instant transfer of money between banks using either a mobile number or email address. That breach involved compromised Westpac customers accounts being used to facilitate the attack.

NAB said the issue was human error and in breach of NAB's data security policies. Credit:James Elsby

In a statement disclosing the breach on Friday night, NAB said personal information provided when customer accounts were set up was uploaded, without authorisation, to the servers of two data service companies.

NAB said its security team had contacted the companies involved, who advised that all information provided to them would be deleted within two hours.