Hundreds of public servants at two small agencies are averaging a month a year in sick leave and other types of unscheduled absences while large departments are resorting to "positive attendance training" to get staff to work.
The rising number of personal leave days taken across the 150,000-person bureaucracy is hurting the nation's productivity with just the increase in sick days registered in recent years being the equivalent of hundreds of years of lost work time.
Almost 400 staff at Aboriginal Hostels Limited and the National Film and Sound Archive took an average of more than 20 days of personal leave a year in 2014-15, according to an Australian Public Service Commission analysis.
Aboriginal Hostels Limited could not comment as of Wednesday while NFSA chief executive Michael Loebenstein said the unusually high figure at his agency was taken "very seriously".
"Unscheduled absence is a complex issue influenced by major factors such as illness and injury, non work-related barriers such as carer responsibilities, as well as motivational factors," Mr Loebenstein said.
"This makes it very hard to generalise."It is a conversation across the whole of the organisation to avoid unintended outcomes such as under reporting of personal leave or, worse, 'presenteeism' where staff feel compelled to come to work when sick."
While the two small agencies had the most hard-core numbers of per worker absenteeism, APSC figures show the federal bureaucracy's "seemingly intractable" problem with sickies was being driven by a dozen large public service agencies with huge workforces.
Thirty thousand staff at the Department of Human Services and another 1000 at Infrastructure and Regional Development each took an average of 14.7 days off last year.
DHS and Infrastructure topped the list of large agencies with the highest unscheduled absence rate.
Next came Department of Social Services staff who took an average of 14.6 days off annually and Department of Agriculture workers [14.2] followed by workers at the Australian Taxation Office [14.1], Department of Veterans Affairs [13.9] and the departments of Finance and Health [12.9].
Immigration and Border Protection workers racked up 12.7 days a year while Employment, Prime Minister & Cabinet and the Australian Bureau of Statistics staff took 12.4 days.
Employees at these dozen organisations recorded higher rates of unscheduled absences than the overall average across the public service of 11.6 days annually.
And together staff at these 12 agencies clocked up a million days off work last financial year.
Unscheduled leave numbers across the bureaucracy are made up primarily of sick leave followed by carer's leave. A very small proportion of unscheduled absences was taken in the form of miscellaneous leave when for times of bereavement as well as unapproved and compensation leave.
A DHS spokesperson said Human Services had sent 3,826 managers to "positive attendance training", "emerging" cases of non-attendance were being red flagged and long-term absences closely monitored.
"Attendance performance management expectations were included in individual performance agreements for supervisors," the spokesperson said.
"The department is committed to achieving higher levels of workforce availability through effective people management, health and safety, and high levels of staff engagement."
The Commonwealth's best performer was the Future Fund Management Agency with 3.7 days per worker.
The best performing large agencies, who recorded unscheduled absences below the the public service average, included Treasury [8.8], Foreign Affairs and Trade [8.8], Industry and Science  and Attorney-General's [11.3].
The Environment [11.8] and Defence [11.9] departments came close to the average across the bureaucracy.
The public service recorded a 1.8 day increase in unscheduled absences in the past four years from 9.8 days per worker to 11.6 days.
In rough terms this increase was equivalent to 700 years off work.
The APSC calculated its figures using full-time equivalent staffing numbers.