A Commonwealth Bank worker has revealed she was sacked after 25 years - but not before she unknowingly training AI to do her job.

Bank teller Kathryn Sullivan, 63, said she was entirely unaware she was helping a chatbot take over her role before she was made redundant in July, ending her long career with the bank.

She said she supported new technologies that improved customer service, however, she was blindsided by the cuts.

'I was completely shell-shocked, alongside my colleague,' she said. 'We just feel like we were nothing, we were a number.'

Ms Sullivan said Commonwealth Bank - which made a $10.25billion profit in the past financial year - failed to communicate with her for more than a week after she was made redundant.