A National Australia Bank employee in Melbourne who "falsified" a positive COVID-19 diagnosis, sparking the evacuation of its offices last week, has been sacked.

The employee's actions sent thousands of colleagues into a panic.

In an email to staff on Monday, chief people officer Susan Ferrier said the bank regretted the stress and uncertainty the incident had caused and said the person would not return to work at NAB.

NAB chief people officer Susan Ferrier said the staffer will not be returning to work at NAB. Credit:Sam Mooy

"Last Tuesday (17 March) we advised that a colleague who worked on the ground floor at 700 Bourke Street had tested positive to COVID-19. We vacated the building for a pandemic clean and our colleagues from 700 Bourke have since been working remotely," Ms Ferrier wrote in the email, seen by The Sydney Morning Herald and The Age.