The workers arrived at their desks at the Department of Foreign Affairs and Trade on April 1 to be confronted with an "announcement" on a big TV screen that their workplace was being broken up and moved to Melbourne.

The message told more than 30 low-ranking public servants at the Australian Passport Office, many of whom are on temporary contracts, they must submit expressions of interest if they wanted to keep their jobs by moving interstate.

Managers at the office's Canberra regional eligibility centre (CREC) left the message on the display for five hours, The Canberra Times understands, despite the growing distress among workers.

A departmental spokeswoman said on Tuesday that DFAT had no comment to make on how its Passport Office staff were treated on April 1.

Public servants at the department have good reason to fear for their employment prospects: DFAT is due to complete the shedding of 500 jobs by June, and future staffing levels are not guaranteed.

There have been even fewer laughs over jobs in the wider bureaucracy: more than 7000 staff were made redundant last year amid an overall reduction of 11,000 Commonwealth workers.

It took until about 2pm on April 1 for one of the centre's supervisors to tell workers that the announcement was an April Fools' Day prank and there was no need for them to worry about their jobs.

The public servants who were the butt of the joke are low-ranking members of the elite department, many of them work part time or on temporary contracts, who spend their days checking that applicants for Australian passports meet the eligibility requirements in a function known internally as ELLO.

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The "announcement" told the workers that the Passport Office was moving to take advantage of "huge centralisation opportunities" and to make use of empty office space in the Victorian capital.

"As a result of all this, CREC's ELLO capacity will be moved to Melbourne this year," the message read. "Advertisements for ELLO positions will be released soon."

This is not the first time ill-considered humour has brought controversy to Foreign Affairs.

Former AusAID staffers were enraged when one of their new DFAT colleagues mimed machine-gunning the massed ranks of AusAIDers who had been bussed in to a joint briefing of the newly merged department in October 2013.

Foreign Affairs bosses threw a cloak of secrecy over their reaction to the incident, which left lasting ill-feeling among the staff drafted into DFAT from the overseas aid agency after it was abolished.