NAB has flagged the loss of 6000 jobs as the impact of new technology and digital transactions cuts a swath through traditional banking jobs.
The job losses over three years were announced as the bank revealed a full-year net profit of $5.3 billion.
In announcing the cuts NAB chief executive Andrew Thorburn said the entire banking industry was under pressure to reshape its workforce.
"As transactions move to digital channels - and this is driven by our customers - we will need fewer people," Mr Thorburn said.
"What we are not saying is that 6000 are going here and here and here, it will be done over three years."
Mr Thorburn said the net job losses would be closer to between 4000 and 2000 as new positions were be created.
More existing bank closures were foreshadowed as well, although Mr Thorburn said new branches would be added in the growth corridors in western Sydney and Melbourne.
The bank is expected to announce restructuring costs relating to the redundancies of between AU$500m and AU$800m in first half results early next year.
The cost-cutting measures were budgeted to save the bank of $1bn by 2020.
NAB said it planned to boost investment in "simplifying" the bank by $1.5 billion over the next three years, on top of an existing $3 billion internal investment program.
The bank planned to halve the number of products it sells and drive 60 percent of its business through digital channels.